Free ASCP MLS Exam Practice Questions Mock Test: Part 12 – (Urinalysis Microscopic )

• Waxy casts are formed in stagnant or severely damaged tubules (e.g., chronic kidney disease, advanced renal failure).

• Key features:

  • High refractive index (appear more “glassy” or “waxy” under the microscope).

  • Sharp, broken, or blunt ends (unlike the tapered ends of hyaline casts).

  • Homogeneous, smooth texture (no granules or inclusions).

  • Yellowish or grayish color (due to degeneration of cellular or granular casts over time).

Why Not the Others?

• a) Granular appearance → Seen in granular casts (degenerated cellular casts).

• c) Presence of RBCs inside → Seen in RBC casts (indicates glomerular bleeding, e.g., glomerulonephritis).

• d) Transparent cylindrical shape → Describes hyaline casts (normal or benign, seen in dehydration/stress).

• Uric acid crystals in an infant are most commonly due to increased purine metabolism, seen in conditions like:

  • Lesch-Nyhan syndrome (HGPRT deficiency)

  • Tumor lysis syndrome (rapid cell turnover)

  • Dehydration (concentrated urine)

• These crystals appear as yellow-brown rhomboids, rosettes, or barrels in acidic urine.

Why Not the Others?

• a) Viral hepatitis – Causes bilirubinuria/urobilinogen, not uric acid crystals.

• b) Ethylene glycol toxicity – Produces calcium oxalate monohydrate (dumbbell) crystals, not uric acid.

• d) Contamination – Unlikely; uric acid crystals are pathologic in infants and warrant metabolic workup

• Ghost RBCs (shadow cells) are hemolyzed red blood cells that appear as pale, empty cell membranes under the microscope.

• They form when RBCs are exposed to hypotonic urine (low specific gravity), causing osmotic lysis and hemoglobin leakage.

• While acidic urine (pH <5.5) can also contribute to RBC degradation, hypotonicity (dilute urine) is the primary driver of ghost cell formation.

Why Not the Others?

• a) Acidic urine (pH 6.5) – Near-neutral pH; significant RBC lysis typically requires pH <5.5.

• c) High ketones – Causes ketonuria but does not directly lyse RBCs.

• d) High glucose – Leads to osmotic diuresis but does not create ghost cells unless urine is also hypotonic.

• Renal tubular epithelial (RTE) cells can closely resemble white blood cells (WBCs) in size and shape, making them difficult to distinguish under the microscope.

• Key differences:

  • RTE cells have a single, round, eccentric nucleus and granular cytoplasm.

  • WBCs (especially neutrophils) typically have multi-lobed nuclei and may show cytoplasmic granules.

Why Not the Others?

• a) Oil droplets – Refractile, spherical, and lack cellular structure (seen in lipiduria).

• c) Sulfonamide crystals – Needle-like or sheaves of wheat appearance (drug-induced crystals).

• d) Squamous epithelial cells – Large, flat, and irregular with small central nuclei (from urethra/vagina, not kidney).

• Calcium oxalate crystals are most commonly found in acidic urine (pH < 6.0).

• They appear as envelopes (dihydrate form) or dumbbell-shaped (monohydrate form) under microscopy.

• Causes include:

  • High oxalate intake (e.g., spinach, nuts)

  • Ethylene glycol poisoning

  • Hypercalciuria

Why Not the Other Options?

• a) Triple phosphate (struvite) – Forms in alkaline urine (pH > 7.0), often due to UTIs with urease-producing bacteria (e.g., Proteus).

• c) Ammonium biurate – Seen in neutral to alkaline urine, associated with liver disease or old urine samples.

• d) Calcium carbonate – Found in alkaline urine and is rare; seen as small, round crystals.

The presence of bacteria and WBCs (white blood cells) without epithelial cells in a urine specimen strongly suggests a true urinary tract infection (UTI) rather than contamination. Here’s why:

• Bacteria + WBCs = Indicative of infection (pyuria and bacteriuria).

• No epithelial cells = Suggests the sample was not contaminated by vaginal or skin flora (which would typically introduce squamous epithelial cells).

Why Not the Other Options?

• a) Contaminated – Contamination usually includes squamous epithelial cells from the skin or vagina.

• b) Vaginal flora – Would likely show epithelial cells and possibly bacteria, but not necessarily WBCs.

• d) Improperly collected – Improper collection often leads to contamination (epithelial cells), but this sample lacks them.

• WBC (white blood cell) casts are pathognomonic for pyelonephritis (kidney infection). They form when neutrophils aggregate inside the renal tubules, indicating active inflammation or infection in the kidney itself.

• Their presence helps differentiate pyelonephritis (upper UTI) from cystitis (lower UTI), where WBCs are present but casts are absent.

Why Not the Other Options?

• a) Oval fat bodies – Seen in nephrotic syndrome (lipiduria), not infection.

• b) Broad casts – Found in chronic kidney disease (CKD), due to tubular dilation and stasis.

• d) Calcium oxalate crystals – Associated with hypercalciuria or ethylene glycol poisoning, unrelated to infection.

• Hyaline casts are the most common type of cast seen in healthy individuals, particularly after strenuous exercise, dehydration, or fever.

• They are composed of Tamm-Horsfall mucoprotein (secreted by renal tubular cells) and appear pale, translucent, and homogeneous under microscopy.

• While they can sometimes indicate mild kidney stress, they are not pathological by themselves and are often transient.

Why Not the Other Options?

• a) Granular cast – Suggests degeneration of cellular casts (e.g., from kidney disease), not a normal finding post-exercise.

• b) Waxy cast – Indicates chronic kidney disease or severe stasis, not a benign condition.

• c) RBC cast – Pathognomonic for glomerular bleeding (e.g., glomerulonephritis), never normal.

• RTE (Renal Tubular Epithelial) cell casts are composed of cells shed from the renal tubules and indicate direct tubular injury or damage. They are seen in conditions like acute tubular necrosis (ATN), interstitial nephritis, or other tubular pathologies.

Why not the others?

• a) Hyaline casts – Formed from normal urinary proteins (Tamm-Horsfall protein) and are nonspecific; may be seen in dehydration or mild kidney irritation.

• b) RBC casts – Indicate glomerular bleeding (e.g., glomerulonephritis), not tubular damage.

• d) Waxy casts – Seen in chronic kidney disease or long-standing stasis, reflecting advanced tubular atrophy rather than acute damage.

• Supravital stains (e.g., Sternheimer-Malbin, Sedi-Stain) enhance the visualization of cellular components and cytoplasmic structures in urine sediment.

• These stains help differentiate:

  • White blood cells (WBCs) – Stained nuclei become more visible.

  • Renal tubular epithelial cells (RTECs) – Cytoplasmic details and nuclear morphology are highlighted.

  • Transitional epithelial cells – Improved distinction from other cell types.

• They also help identify degenerated vs. viable cells (e.g., in pyelonephritis or ATN).

Why Not the Others?

• a) Crystals → Identified better with polarized microscopy or pH-dependent solubility tests (stains are less useful).

• b) Casts → Hyaline casts may take up stain, but granular/waxy casts are usually identifiable without staining.

• d) Bacteria → Gram stain is superior for bacterial identification; supravital stains provide limited help.

• Hexagonal crystals are pathognomonic for cystinuria, an inherited disorder causing excessive cystine excretion in urine.

• These crystals are flat, colorless, and often stack in layers, forming a classic hexagonal shape.

Why Not the Others?

• b) Tyrosine → Fine, needle-like crystals (seen in tyrosinemia or liver disease).

• c) Leucine → Yellow-brown, spherical crystals with concentric circles (seen in maple syrup urine disease or severe liver disease).

• d) Cholesterol → Colorless, flat plates with notched corners (seen in nephrotic syndrome, not typically in urine sediment).

• Broad waxy casts are pathognomonic for chronic renal failure or advanced kidney disease.

• They form in dilated, atrophic tubules due to prolonged stasis, giving them a wide, brittle, smooth appearance with sharp edges.

• Their presence indicates long-standing kidney dysfunction, such as in end-stage renal disease (ESRD).

Why Not the Others?

• a) Fatty casts – Seen in nephrotic syndrome (e.g., lipiduria from glomerular diseases).

• c) Hyaline casts – Nonspecific, seen in dehydration, exercise, or mild kidney irritation (not chronic failure).

• d) Granular casts – Indicate acute tubular injury (e.g., ATN) or breakdown of cellular debris, not chronicity.

• Cholesterol crystals appear as colorless, rectangular plates with distinct notched corners, often layered or stacked.

• They are typically seen in nephrotic syndrome due to lipiduria (fatty casts and oval fat bodies may also be present).

Why Not the Others?

• a) Cystine – Hexagonal plates (pathognomonic for cystinuria).

• b) Uric acid – Yellow-brown rhomboids or rosettes (seen in acidic urine, gout, or tumor lysis).

• c) Isoleucine – Not a classic urine crystal; leucine crystals (if present) are yellow-brown spheres with concentric circles.

• Leukocyte esterase is an enzyme found in neutrophils, and a positive test indicates the presence of white blood cells (WBCs) in urine, termed pyuria.

• Pyuria is a hallmark of urinary tract infection (UTI) but can also occur in sterile inflammation (e.g., interstitial nephritis).

Why Not the Others?

• a) Hematuria – Detected by the blood pad (hemoglobin/RBCs), not leukocyte esterase.

• c) Ketosis – Detected by the ketone pad (nitroprusside reaction), unrelated to WBCs.

• d) Hyperbilirubinemia – Detected by the bilirubin pad (diazotization), unrelated to inflammation.

Conclusion:
Leukocyte esterase positivity (b) signals pyuria, prompting evaluation for UTI or other causes of inflammation.

• Amorphous phosphates are white, chalky precipitates that form in alkaline urine (pH >7.0).

• They consist of magnesium ammonium phosphate and calcium phosphate, which are soluble in acidic urine but precipitate in alkaline conditions.

• Unlike amorphous urates (seen in acidic urine), phosphates dissolve when urine is acidified.

Why Not the Others?

• a) Acidic urine – Favors amorphous urates (yellow-red granules).

• c) Concentrated urine – May increase crystal formation but does not determine phosphate vs. urate type.

• d) Dilute acidic urine – Inhibits crystal formation; phosphates require alkalinity.

• Red blood cells (RBCs) in urine sediment typically appear as small, round, biconcave discs with central pallor (a lighter center) under the microscope.

• They are non-nucleated and measure 6–8 µm in diameter.

• Morphology clues:

  • Dysmorphic RBCs: Irregular shapes (e.g., blebs, spikes) suggest glomerular bleeding (e.g., glomerulonephritis).

  • Ghost RBCs: Pale, empty membranes due to lysis in dilute or acidic urine.

Why Not the Others?

• b) Urothelial cells – Larger, with eccentric nuclei; line the bladder/ureters.

• c) White blood cells (WBCs) – Larger (10–14 µm), granular, and often lobed nuclei (if visible).

• d) Tyrosine crystals – Needle-like or sheaf-shaped, unrelated to RBCs.

• Sudan III and Oil Red O are fat-soluble stains used to detect neutral lipids (like triglycerides and cholesterol) in urine sediment, particularly in oval fat bodies (lipid-laden renal tubular epithelial cells).

• These stains bind to lipids, causing them to appear orange-red (Sudan III) or bright red (Oil Red O) under microscopy.

Why Not the Other Options?

• a) Gram stain – Used for bacterial identification (differentiates Gram-positive vs. Gram-negative).

• b) Prussian blue – Detects iron (e.g., hemosiderin in urine, not lipids).

• d) Wright’s stain – Used for blood smears (e.g., WBC differentials, not lipids).

Yeast cells in urine can sometimes resemble red blood cells (RBCs) in size and shape, but a key distinguishing feature is:

• Budding, which is characteristic of yeast replication (e.g., Candida species)

• Yeast may also form pseudohyphae under certain conditions

Why Other Options Are Incorrect:

• a) Uniform size → RBCs are more uniform; yeast can vary.

• c) Refractile under light → RBCs are more refractile than yeast.

• d) Smaller than RBCs → Yeast are typically similar or slightly larger (e.g., Candida ~8-12 µm).

• Uric acid crystals commonly appear as colorless or yellow-brown rhombic plates or rosettes in acidic urine (pH <6.0).

• They are associated with gout, hyperuricemia, dehydration, or tumor lysis syndrome.

Why Not the Others?

• a) Leucine – Yellow-brown spheres with concentric circles (seen in liver disease or maple syrup urine disease).

• c) Cholesterol – Rectangular plates with notched corners (found in nephrotic syndrome).

• d) Triple phosphate – Colorless “coffin-lid” prisms (alkaline urine, UTI-related).

• Ethylene glycol poisoning leads to the formation of calcium oxalate monohydrate crystals, which appear as dumbbell-shaped or needle-like structures in urine.

• These crystals result from the metabolism of ethylene glycol into oxalic acid, which binds calcium in the kidneys.

Why Not the Others?

• a) Yellow-brown spherules (leucine) – Seen in maple syrup urine disease or severe liver disease, not ethylene glycol toxicity.

• c) Rosettes (uric acid) – Found in gout or tumor lysis syndrome, unrelated to ethylene glycol.

• d) Notched plates (cholesterol) – Associated with nephrotic syndrome, not toxin ingestion.

Triple phosphate crystals (also known as struvite crystals) are:

• Found in alkaline urine

• Typically colorless, coffin-lid shaped

• Common in urinary tract infections with urease-producing bacteria (e.g., Proteus species)

• Often considered nonpathologic when seen in small numbers, especially in alkaline urine

However, persistent or abundant triple phosphate crystals can suggest UTI or struvite stone formation, making them potentially clinically significant — but not inherently pathologic just by their presence.

❌ Incorrect options:

• a) Acidic and pathologic – Triple phosphate forms in alkaline, not acidic, urine.

• b) Alkaline and pathologic – They form in alkaline urine but are not always pathologic.

• c) Acidic and nonpathologic – Incorrect urine pH.

• Birefringence refers to the property of a material to refract light in two different directions, producing a “Maltese cross” or colorful appearance under polarized microscopy.

• Uric acid crystals are strongly birefringent and display bright colors (yellow, blue, pink) under polarized light.

Why Not the Other Options?

• a) Hyaline cast – Made of Tamm-Horsfall protein; not birefringent (appears clear under brightfield and polarized light).

• c) WBC (White Blood Cells) – Do not exhibit birefringence.

• d) Fatty cast – Contains lipids (e.g., cholesterol), which may show anisotropy (weak birefringence) but are less distinct compared to uric acid crystals.

• A true WBC cast is confirmed by the presence of leukocytes (WBCs) embedded within a cast matrix, which distinguishes it from a clump of free-floating WBCs.

• The proteinaceous cast matrix (Tamm-Horsfall mucoprotein) is the key feature proving renal tubular origin.

Why Not the Others?

• a) Positive nitrite → Indicates bacteriuria (suggests UTI but does not confirm a WBC cast).

• b) Positive leukocyte esterase → Only confirms WBCs in urine (not whether they are in a cast).

• d) Free-floating WBCs → Seen in cystitis or contamination (not indicative of renal origin)

Glitter cells are neutrophils with refractile cytoplasmic granules that exhibit Brownian motion in hypotonic urine. These granules “glitter” under phase-contrast microscopy, making it the best method for their identification.

• Urine pH >8.0 is unusually alkaline and raises suspicion for:

  • Bacterial overgrowth (urease-producing bacteria like Proteus convert urea to ammonia).

  • Improper storage (delayed testing allows bacterial growth).

  • Contamination (e.g., cleaning agents).

• Clinical causes (e.g., renal tubular acidosis) typically show pH 5.5–7.0, not extreme alkalinity.

Why Not the Others?

• a) Normal pH – Normal range is 4.5–8.0; 8.5 is pathologic or artifactual.

• c) Dehydration – Concentrates urine but does not alkalinize it.

• d) Renal tubular acidosis (RTA) – Type 1 RTA causes inability to acidify urine, but pH rarely exceeds 7.5.

Conclusion:
pH 8.5 (b) should first prompt retesting a fresh sample to rule out preanalytical error.

• Acidic urine (pH <6.0) promotes the formation of calcium oxalate crystals, which appear as envelope-shaped (dihydrate) or dumbbell-shaped (monohydrate) under microscopy.

• These are among the most common crystals in kidney stones (70-80% of cases).

Why Not the Others?

• a) Ammonium biurate – Forms in alkaline urine (pH >7.0), often due to UTIs with urease-producing bacteria (e.g., Proteus).

• b) Calcium phosphate – Precipitates in alkaline urine (associated with metabolic conditions like hyperparathyroidism).

• d) Triple phosphate (struvite) – Requires alkaline urine and forms coffin-lid-shaped crystals in infection-related stones.

• Candida species in urine sediment often exhibit a characteristic budding yeast appearance with pseudohyphae (elongated, chain-like structures formed by connected yeast cells).

• This finding is common in urinary tract infections (UTIs), particularly in:

  • Diabetic patients

  • Immunocompromised individuals

  • Those with prolonged catheter use

  • Patients on long-term antibiotics

Why Not the Other Options?

• a) Trichomonas – A motile parasite with flagella, not budding yeast.

• c) Renal epithelial cells – Kidney tubule cells, which are larger and lack budding or hyphae.

• d) Transitional epithelial cells – Derived from the bladder/ureters; may appear round or caudate but do not show fungal morphology.

• Glitter cells are neutrophils (WBCs) that exhibit Brownian motion of cytoplasmic granules when suspended in hypotonic (dilute) urine (specific gravity <1.010).

• This creates a “glittering” appearance under the microscope, caused by the granules’ movement as water enters the cells.

• While glitter cells are often associated with pyelonephritis, they can also occur artifactually due to dilute urine (e.g., excessive hydration).

Why Not the Others?

• a) RBCs in concentrated urine – RBCs crenate (shrink) in hypertonic urine but do not “glitter.”

• b) RBCs in dilute urine – RBCs lyse (form ghost cells) in hypotonic urine, but their granules do not move.

• c) WBCs in concentrated urine – WBCs shrivel without granule movement; glittering requires hypotonicity.

• High dry power (40× objective) is the standard magnification for routine urine sediment analysis, providing optimal detail for identifying and enumerating:

  • RBCs (small, smooth, non-nucleated discs).

  • WBCs (larger, granular, may show nuclei).

  • Bacteria (tiny rods or cocci, often with Brownian motion).

• This magnification balances field size (for counting) and resolution (for differentiation).

Why Not the Others?

• a) Low power (10×) – Used for initial scanning of casts (e.g., hyaline, granular) but lacks detail for cells/bacteria.

• c) Oil immersion (100×) – Reserved for bacterial morphology (e.g., rods vs. cocci) or fine details, not routine counts.

• d) Phase contrast – Enhances visibility of hyaline casts or faint elements but isn’t required for standard enumeration.

• Broad waxy casts are formed in dilated tubules of chronically damaged kidneys, indicating advanced renal dysfunction and stasis of urine flow.

• They are composed of degenerated protein material (from compacted cellular casts) and appear homogeneous, brittle, and highly refractive under microscopy.

• Their presence suggests long-standing kidney disease, such as:

  • Chronic kidney disease (CKD)

  • End-stage renal failure

Why Not the Other Options?

• a) Acute glomerulonephritis – Typically causes RBC casts or cellular casts, not broad waxy casts.

• b) Pyelonephritis – Usually associated with WBC casts or bacteria, not waxy casts.

• d) Nephrotic syndrome – Leads to fatty casts or oval fat bodies, not broad waxy casts.

Cholesterol crystals in urine typically appear as colorless, thin, flat plates with characteristic notched corners. These crystals are often seen in acidic urine and may indicate pathological conditions such as nephrotic syndrome or lipiduria.

Other options explained:

• b) Needles arranged in sheaves → Typical of calcium oxalate monohydrate or tyrosine crystals.

• c) Coffin-lid structures → Seen in triple phosphate (struvite) crystals.

• d) Dumbbells → Characteristic of calcium oxalate dihydrate crystals.

• Hyaline casts are clear, smooth, and cylindrical, composed primarily of Tamm-Horsfall mucoprotein.

• They are non-pathologic (seen in dehydration, exercise, or normal urine) but may increase in mild renal stress.

Why Not the Others?

• a) Waxy – Opaque, dense, and brittle (indicative of chronic kidney disease).

• b) Cellular – Contains embedded cells (e.g., RBCs, WBCs, or renal tubular cells).

• d) Granular – Rough-textured from degenerated cellular debris (seen in ATN or CKD).

• Trichomonas vaginalis, a sexually transmitted protozoan parasite, is characterized by its rapid, jerky (darting) motility in fresh urine specimens.

• It is pear-shaped with flagella and can be identified under the microscope by its twitching movements, especially in warm, freshly voided urine.

Why Not the Others?

• a) Yeast – Appears as small, oval budding cells with no motility.

• c) Bacteria – May show Brownian movement (random vibration), but not true directional motility.

• d) WBC (White Blood Cells) – Are non-motile in urine sediment (though they may show slight cytoplasmic streaming in hypotonic urine).

• Squamous epithelial cells are large, flat cells with irregular borders and a small central nucleus.

• They originate from the urethra and vaginal lining, making them common in female urine due to contamination during sample collection.

• Their presence in large numbers usually indicates improper midstream clean-catch technique rather than a pathological condition.

Why Not the Others?

• a) RTE (Renal Tubular Epithelial) cells – Indicate kidney damage (e.g., ATN, nephritis) and are not normal contaminants.

• b) Transitional (urothelial) cells – Line the bladder/ureters; increased numbers may suggest irritation or malignancy, but they are not typical contaminants.

• d) Glitter cells – Degenerated WBCs (neutrophils) seen in pyelonephritis or hypotonic urine, unrelated to contamination.

• Casts are best visualized under low-power magnification (10× objective) with reduced light (dim condenser) to enhance contrast.

  • Hyaline casts are transparent and easily missed under bright light.

  • Dim light highlights their refractile edges and trapped inclusions (e.g., cells, granules).

• Higher magnifications (40×) are used to detail cellular components within casts (e.g., RBCs, WBCs), but initial screening is done at 10×.

Why Not the Others?

• a) Glacial acetic acid – Dissolves amorphous phosphates but can lyse casts; not used for routine cast examination.

• b) Bright light at 40× – Obscures hyaline casts; useful only for cellular/granular casts.

• c) Sternheimer-Malbin stain – Enhances WBC/RTE cell visibility but is not routine for cast screening.

• The urine dipstick test for blood detects heme pigments, including hemoglobin (from RBCs or hemolysis) and myoglobin (from muscle breakdown, e.g., rhabdomyolysis).

• Myoglobinuria gives a false-positive “blood” result because myoglobin contains heme, but no RBCs are seen on microscopy.

Why Not the Others?

• b) Hematuria – A true positive (RBCs present in urine).

• c) Pyuria – Detected by leukocyte esterase, not the blood pad.

• d) Hyperbilirubinemia – Causes dark urine but does not react with the blood pad.

Conclusion:
Myoglobinuria (a) is a classic false-positive for blood on dipsticks, requiring CK levels and microscopy (no RBCs) for confirmation.

• Cholesterol crystals are most commonly seen in nephrotic syndrome, where heavy proteinuria (3–4+) leads to lipiduria (fatty casts, oval fat bodies, and cholesterol crystals).

• They appear as colorless, rectangular plates with notched corners and are unrelated to urine pH or glucose/ketone levels.

Why Not the Others?

• a) pH 8.0 – Cholesterol crystals are pH-independent (unlike phosphate/urate crystals).

• c) Ketones 40 mg/dL – Indicates starvation or DKA but does not correlate with cholesterol crystals.

• d) Glucose 500 mg/dL – Suggests diabetes mellitus but is unrelated to cholesterol crystals.

• Urinary casts are formed when uromodulin (Tamm-Horsfall protein), a glycoprotein secreted by renal tubular cells (thick ascending limb of Henle), precipitates and traps other elements (e.g., cells, debris) in the tubules.

• This protein is the primary matrix of all casts, including:

  • Hyaline casts (pure Tamm-Horsfall protein).

  • Cellular casts (e.g., RBC, WBC, RTE cells embedded in the matrix).

  • Granular/waxy casts (degenerated cellular material within the protein framework).

Why Not the Others?

• a) Albumin – Prominent in proteinuria (e.g., nephrotic syndrome) but does not form casts.

• b) Globulins – Seen in multiple myeloma (Bence Jones proteinuria) but are not cast matrices.

• c) Paraprotein (e.g., light chains) – Can form myeloma casts but are pathologic exceptions, not the universal cast component.

• Neutral fats (triglycerides) exhibit birefringence under polarized light, appearing as Maltese cross patterns (characteristic of lipid droplets in nephrotic syndrome).

• This property helps differentiate them from other lipids (e.g., cholesterol esters, which do not show this pattern).

Why Not the Others?

• a) Cholesterol – Forms notched rectangular plates but does not show Maltese crosses (cholesterol esters may, but free cholesterol does not).

• b) Triglycerides – A subset of neutral fats (correct, but less specific than option d).

• c) Fatty acids – Rarely seen in urine; do not polarize like neutral fats.

• Budding yeast cells (often with pseudohyphae) in acidic, glucose-rich urine are characteristic of Candida albicans, a common fungal infection.

• Risk factors include diabetes mellitus, antibiotic use, or immunosuppression.

Why Not the Others?

• a) E. coli – A bacterium (rods on microscopy), not yeast.

• c) Trichomonas vaginalis – A motile protozoan, unrelated to budding.

• d) Enterobius vermicularis (pinworm) – A helminth, detected via tape test, not urine.

• Amorphous urates are urates (e.g., sodium, potassium, magnesium urate) that appear as granular, pink-orange sediment in urine.

• They precipitate in acidic urine (pH < 6.0) due to the low solubility of uric acid in acidic conditions.

• Under the microscope, they resemble fine granular debris and may form brick-red or yellow-brown clumps.

Why Not the Other Options?

• a) Alkaline urine – Favors amorphous phosphates (white/gray, chalky appearance), not urates.

• c) Highly diluted urine – Dilution reduces precipitation; urates form better in concentrated acidic urine.

• d) Midstream clean-catch urine – Collection method does not influence urate formation; pH does.

Waxy casts are a type of urinary cast that forms in the kidney tubules. They are associated with:

• Chronic kidney disease (CKD)

• Advanced renal failure

• Long-standing tubular damage

They indicate poor urine flow and stasis in the tubules, often seen in severe, long-term kidney dysfunction.

Why not the other options?

• b) Acute inflammation → Typically associated with white blood cell (WBC) casts or cellular casts.

• c) Glomerular damage → More likely to show RBC casts or proteinuria.

• d) Dehydration → May cause hyaline casts but not waxy casts.

• Urine pH directly influences crystal formation because certain crystals only precipitate in specific pH ranges:

  • Acidic urine (pH <6.0): Favors uric acid, calcium oxalate, and cystine crystals.

  • Alkaline urine (pH >7.0): Favors triple phosphate (struvite), calcium phosphate, and ammonium biurate crystals.

• This principle is critical for diagnosing metabolic disorders (e.g., gout, cystinuria) or infection-related stones (e.g., struvite).

Why Not the Others?

• b) Nitrite indicates infection – Unrelated to crystal formation (nitrite signals bacteriuria).

• c) Protein affects precipitation – Proteinuria causes casts/lipiduria (e.g., cholesterol crystals) but doesn’t dictate pH-dependent crystallization.

• d) Specific gravity reflects concentration – While concentrated urine promotes crystallization, pH determines which crystals form.

Conclusion:
Urine pH (a) is essential for identifying crystals because their solubility and type are pH-dependent.

• Renal tubular epithelial cells (RTECs) are significant because their presence indicates kidney damage or disease, such as acute tubular necrosis (ATN), glomerulonephritis, or renal allograft rejection.

• They originate from the nephrons and are not commonly seen in healthy individuals.

Why Not the Others?

• a) Squamous epithelial cells: Commonly found in urine but usually insignificant—they originate from the urethra or genital tract and often indicate contamination (e.g., improper sample collection).

• b) Transitional epithelial cells: Line the bladder, ureters, and renal pelvis. While a few are normal, large numbers or clusters may suggest bladder irritation, infection, or malignancy (e.g., urothelial carcinoma). However, they are less clinically significant than RTECs.

• d) “All are insignificant” is incorrect because RTECs are always clinically relevant.

Renal tubular cells typically have eccentric nuclei (off-center) and a granular cytoplasm, while transitional epithelial cells (from the urinary bladder/ureters) usually have central or slightly eccentric nuclei and may have a more uniform appearance.

Key Differences:

• Renal tubular cells: Eccentric nuclei, granular cytoplasm.

• Transitional cells: Central or slightly eccentric nuclei, often larger and polygonal.

Other options:

• a) Larger size – Transitional cells are generally larger.

• b) Central nuclei – More typical of transitional cells.

• d) Smaller size – Renal tubular cells are not consistently smaller.

• Tyrosine crystals (slender needles in clusters or rosettes) – Seen in liver failure, tyrosinemia, and severe metabolic disorders.

• Leucine crystals (yellow-brown spheres with concentric circles) – Also associated with liver disease and maple syrup urine disease.

Other options explained:

• a) Cystine crystals → Seen in cystinuria (a genetic disorder), not specifically liver disease.

• c) Uric acid crystals → Associated with gout, high-purine diets, or tumor lysis syndrome, not liver disease.

• d) Ammonium biurate crystals (“thorny apple” appearance) – Found in alkaline urine and may indicate UTI with urea-splitting bacteria, but not specifically liver disease.

• Bacilli in urine sediment often correlate with positive nitrite, as many gram-negative bacteria (e.g., E. coli, Proteus) reduce urinary nitrate to nitrite.

• This combination suggests a UTI, especially if paired with WBCs or leukocyte esterase.

Why Not the Others?

• a) Ketones – Associated with starvation/DKA, not bacteriuria.

• b) Glucose – May promote bacterial growth but doesn’t directly correlate with bacilli.

• c) Specific gravity – Reflects urine concentration but doesn’t predict infection.

Conclusion:
Bacilli + nitrite (d) strongly indicate UTI, warranting culture if symptomatic.

• The Ehrlich reaction is the chemical basis for detecting urine urobilinogen on reagent strips.

  • p-Dimethylaminobenzaldehyde (Ehrlich’s reagent) reacts with urobilinogen to produce a pink-red color.

• Urobilinogen is a breakdown product of bilirubin, elevated in hemolysis or liver dysfunction.

Why Not the Others?

• a) Ketones – Uses nitroprusside reaction (lavender color).

• c) Bilirubin – Relies on diazotization (tan/purple with diazo dyes).

• d) Glucose – Based on glucose oxidase/peroxidase (green to brown).

Conclusion:
Urobilinogen (b) is the only test using the Ehrlich reaction, critical for evaluating jaundice/hemolysis.

• Calcium oxalate dihydrate crystals are most commonly recognized by their distinctive octahedral (eight-sided) or envelope-shaped appearance under the microscope.

• These colorless, refractile crystals are typically seen in neutral or acidic urine and are associated with:

  • Dietary intake of oxalate-rich foods (spinach, nuts, tea).

  • Ethylene glycol poisoning (if abundant).

  • Idiopathic calcium oxalate crystalluria.

Why Not the Others?

• a) Coffin-lid → Describes triple phosphate (struvite) crystals, seen in alkaline urine with UTI.

• c) Dumbbell → Characteristic of calcium oxalate monohydrate crystals (smaller, oval/elongated forms).

• d) Rosette → Seen in uric acid crystals (radiating needle clusters) or cystine crystals (hexagonal rosettes in cystinuria).

• Cystine crystals are pathognomonic for cystinuria, a rare autosomal recessive genetic disorder that causes defective renal reabsorption of cystine (along with ornithine, lysine, and arginine) in the proximal tubule.

• These hexagonal, flat, colorless crystals appear in acidic urine and can form kidney stones.

• Diagnosis:

  • Urine microscopy (characteristic crystals).

  • 24-hour urine cystine quantification (>250 mg/day is diagnostic).

  • Genetic testing (mutations in SLC3A1 or SLC7A9 genes).

Why Not the Others?

• a) Nephrotic syndrome → Associated with lipiduria (oval fat bodies, fatty casts) but not cystine crystals.

• c) Gout → Linked to uric acid crystals (needle-shaped, yellow-brown), not cystine.

• d) Alkaline urine → Favors triple phosphate (struvite) or calcium phosphate crystals, not cystine (which forms in acidic urine).

Treatment Implications:

• High fluid intake (>3–4 L/day).

• Alkalinization of urine (pH >7.5 with potassium citrate).

• Chelating agents (e.g., tiopronin, penicillamine) if conservative measures fail.

• Radiographic dye (e.g., iodinated contrast media) crystals can resemble cholesterol crystals under polarized light because both may exhibit birefringence (colorful interference patterns).

• Cholesterol crystals typically appear as notched, rectangular plates with strong birefringence, while radiographic dye may form needle-like or rhomboid crystals with similar optical properties.

Why Not the Others?

• a) Cystine – Forms hexagonal plates, distinct from cholesterol.

• b) Uric acid – Appears as yellow-brown rhomboids or rosettes, not easily confused with cholesterol.

• d) Tyrosine – Seen as fine needles or sheaves, unrelated to cholesterol’s appearance.

• Bacteria in urine sediment typically exhibit rapid, random vibratory movement (Brownian motion) due to their small size and collisions with water molecules.

• They appear as tiny, faint, rod-shaped (bacilli) or spherical (cocci) particles, often in clusters or chains.

• True motility (directional movement) is rare in most urinary bacteria, except for certain species like Proteus.

Why Not the Others?

• b) Refractile bodies – Seen in lipid droplets or yeast, not bacteria.

• c) Budding forms – Characteristic of yeast (e.g., Candida).

• d) Concentric striations – Found in leucine crystals, not bacteria.

• RBC casts are pathognomonic for glomerular injury, as they form when red blood cells leak through damaged glomerular capillaries and become trapped in the tubular lumen, forming a cast.

• They are most commonly seen in glomerulonephritis (e.g., IgA nephropathy, post-streptococcal GN) or vasculitis (e.g., lupus nephritis, ANCA-associated vasculitis).

Why Not the Others?

• a) Cystitis → Causes free RBCs or WBCs in urine but no casts (lower urinary tract only).

• b) Pyelonephritis → Associated with WBC casts, not RBC casts.

• d) Nephrotic syndrome → Presents with proteinuria, fatty casts, or oval fat bodies—not RBC casts.

• Renal tubular epithelial (RTE) cell casts are formed when damaged or necrotic tubular cells shed into the tubules and become embedded in a protein matrix.

• They strongly suggest acute tubular necrosis (ATN) or other tubular injury (e.g., ischemia, toxins).

Why Not the Others?

• a) Pyelonephritis → Typically causes WBC casts, not RTE casts.

• c) Glomerulonephritis → More associated with RBC casts or hyaline/granular casts.

• d) Nephrotic syndrome → Presents with fatty casts or oval fat bodies, not RTE casts.

• Lipid droplets (found in oval fat bodies or free-floating) exhibit a Maltese cross pattern under polarized light due to their cholesterol content.

• This is a classic feature seen in nephrotic syndrome, where heavy proteinuria leads to lipiduria.

Why Not the Other Options?

• a) Hyaline casts – Do not contain lipids and appear structureless; they do not polarize light.

• b) WBCs (White Blood Cells) – Do not show birefringence or a Maltese cross pattern.

• d) Uric acid crystals – Are birefringent but appear in various colors and shapes (e.g., rhombic or rosettes), not a Maltese cross.

• A positive nitrite test indicates the presence of bacteria that reduce urinary nitrates to nitrites, primarily gram-negative rods (e.g., E. coli, Klebsiella, Proteus).

• This is a key screening marker for UTI, especially when paired with leukocyte esterase or WBCs.

Why Not the Others?

• a) Gram-positive cocci (e.g., Enterococcus) – Do not reduce nitrates, yielding false-negative nitrite results.

• b) Yeast – Fungal infections do not produce nitrites.

• d) Epithelial cells – Indicate contamination (e.g., vaginal/skin flora) but are unrelated to nitrites.

Conclusion:
Nitrite positivity (c) signals gram-negative, nitrate-reducing bacteria, prompting culture if symptoms suggest UTI.

• Yeast cells (e.g., Candida spp.) can closely resemble RBCs in size and shape under the microscope, but they are distinguished by two key features:

  1. High refractility – Yeast cells often appear more sharply refractive (glittering) due to their rigid cell wall.

  2. Budding – Yeast may show small daughter cells budding from the parent cell, a feature never seen in RBCs.

• Unlike RBCs, yeast cells are oval or round and may form pseudohyphae in infections.

Why Not the Others?

• a) WBCs – Granular cytoplasm and lobed nuclei (if visible) differentiate them from RBCs; no refractility/budding.

• c) Squamous cells – Large, flat, and irregularly shaped with small nuclei; unrelated to RBCs.

• d) Transitional cells – Larger, with prominent nuclei; no refractility or budding.

• Squamous epithelial cells are large, flat cells that originate from the urethra, vagina, or external genitalia. Their presence in urine is a classic sign of contamination with vaginal secretions, particularly in women.

• These cells are not of renal origin and do not indicate kidney disease.

Why Not the Other Options?

• a) Waxy casts – Formed in the kidney tubules due to chronic stasis (e.g., chronic kidney disease); unrelated to contamination.

• c) Broad casts – Also renal in origin, seen in advanced kidney disease; not linked to vaginal contamination.

• d) Renal tubular cells – Indicate kidney injury (e.g., acute tubular necrosis), not contamination.

• A fruity/sweet urine odor is classic for ketonuria, caused by acetone (a ketone body) in conditions like:

  • Diabetic ketoacidosis (DKA)

  • Starvation/fasting

• Ketones are detected via dipstick (nitroprusside reaction) or odor.

Why Not the Others?

• a) Bilirubin – Causes dark, foamy urine but no distinct odor.

• b) Urea – Normal urine odor; ammoniacal smell if stale (due to bacterial urea breakdown).

• d) Ammonia – Pungent odor from UTI with urease bacteria (e.g., Proteus), not fruity.

Conclusion:
Fruity odor (c) signals ketones, urgently requiring evaluation for DKA if paired with hyperglycemia.

• Glycosuria refers to the abnormal presence of glucose in urine, typically due to:

  • Hyperglycemia (e.g., uncontrolled diabetes mellitus).

  • Renal glycosuria (defective tubular reabsorption, e.g., Fanconi syndrome).

• Detected via reagent strips (glucose oxidase reaction) or Clinitest.

Why Not the Others?

• b) Hematuria – RBCs in urine (from trauma, infection, or glomerular disease).

• c) Pyuria – WBCs in urine (sign of inflammation/infection).

• d) Albuminuria – Protein (albumin) in urine (e.g., nephrotic syndrome).

Conclusion:
Glucose in urine (a) is termed glycosuria, a key finding in diabetes or renal dysfunction.

Ghost RBCs are red blood cells that have lysed, losing their hemoglobin and appearing as pale, empty cell membranes under the microscope. This typically occurs when RBCs are exposed to dilute or alkaline urine, which causes osmotic lysis.

Key associations:

• Alkaline urine or very dilute urine → causes RBCs to swell and lyse

• Ghost cells are often seen in older specimens or those with high pH

Why the other options are incorrect:

• a) Concentrated urine – Preserves RBCs better; less likely to form ghost cells

• c) Fresh specimens – Less likely to show ghost cells because RBCs haven’t lysed yet

• d) Highly acidic urine – Helps preserve RBC morphology; doesn’t lead to ghost cells

• Trichomonas vaginalis is a flagellated protozoan parasite that causes trichomoniasis, a sexually transmitted infection.

• When observed in urine sediment under a microscope, it exhibits characteristic jerky or twitching motility due to its flagella.

• It is often seen in wet mount preparations of urine or vaginal/cervical samples.

Why Not the Others?

• a) E. coli: A bacterium that may cause UTIs but does not exhibit jerky motility in urine sediment.

• c) Candida albicans: A yeast that may appear as budding cells or pseudohyphae but lacks motility.

• d) Schistosoma haematobium: A parasitic worm (trematode) whose eggs may appear in urine, but the organism itself does not show jerky motility.

• Fiber-like artifacts in urine sediment are typically contaminants (e.g., from clothing, gauze, or filter paper).

• They are elongated, irregular, and lack cellular or cast features, distinguishing them from true pathologic elements.

Why Not the Others?

• b) Waxy cast – Smooth, dense, and homogeneous (indicative of chronic kidney disease).

• c) Hyaline cast – Clear, cylindrical, and nonspecific (from Tamm-Horsfall protein).

• d) Granular cast – Composed of degenerated cellular debris (seen in ATN or CKD).

• Clue cells are vaginal squamous epithelial cells coated with Gardnerella vaginalis and other bacteria, giving them a stippled or granular appearance under the microscope.

• They are the hallmark diagnostic feature of bacterial vaginosis (BV), a common vaginal imbalance caused by overgrowth of anaerobic bacteria.

• Clue cells are identified in vaginal wet mounts, not urine sediment.

Why Not the Others?

• b) Ghost cells – Degenerated RBCs in urine, associated with glomerular bleeding or dilute urine.

• c) Glitter cells – WBCs in urine showing Brownian motion, linked to pyelonephritis or dilute urine.

• d) Oval fat bodies – Lipid-laden renal tubular cells in urine, indicative of nephrotic syndrome.

• Squamous epithelial cells are large, flat cells with irregular borders, commonly originating from the urethra, vagina, or perineal skin.

• Their abundant presence with negative leukocyte esterase (no WBCs) and nitrite (no bacteria) strongly suggests contamination during sample collection, especially in women.

• This finding highlights the need for proper midstream clean-catch technique to avoid false interpretations.

Why Not the Others?

• b) Improper refrigeration – Causes degeneration of cells/bacteria but doesn’t selectively increase squamous cells.

• c) Urinary tract infection (UTI) – Expected positive leukocyte esterase/nitrite and WBCs/bacteria, not squamous cells alone.

• d) Chronic kidney disease (CKD) – Associated with broad waxy casts or RTE cells, not squamous contamination.

• Renal tubular epithelial cell (RTEC) casts are pathognomonic for ATN. They form when sloughed-off tubular cells become embedded in the Tamm-Horsfall protein matrix within the tubules.

• Key features of ATN in urine sediment:

  • RTEC casts (most specific finding).

  • Muddy brown granular casts (degenerated RTECs).

  • Free-floating RTECs (often with irregular nuclei or vacuolated cytoplasm).

Why Not the Others?

• a) Hyaline casts → Seen in dehydration/stress (not specific to ATN).

• b) RBC casts → Indicate glomerular bleeding (e.g., glomerulonephritis, vasculitis).

• c) Granular casts → May occur in ATN but are non-specific (also seen in chronic kidney disease, strenuous exercise).

• Oval fat bodies are renal tubular epithelial cells that have absorbed lipids (cholesterol and triglycerides) and appear as rounded cells with fat droplets inside.

• They are most commonly seen in nephrotic syndrome, where heavy proteinuria (especially albumin loss) leads to increased lipid filtration and reabsorption by tubular cells.

• Under polarized microscopy, these fat droplets show a Maltese cross pattern due to their cholesterol content.

Why Not the Other Options?

• a) Cystitis – Involves bladder inflammation, not lipid-laden tubular cells.

• c) Glomerulonephritis – May cause hematuria or proteinuria but not typically oval fat bodies.

• d) Pyelonephritis – A kidney infection causing WBCs and bacteria in urine, not lipid-containing cells.

• Dysmorphic red blood cells (RBCs) in urine are irregularly shaped, often with blebs or protrusions, indicating they have passed through the glomerular basement membrane (a hallmark of glomerular bleeding).

• Their presence strongly suggests a renal (kidney) origin, such as:

  • Glomerulonephritis

  • IgA nephropathy

  • Other glomerular diseases

Why Not the Other Options?

• a) Lower urinary tract infection (UTI) – Typically causes isomorphic (uniform) RBCs, as they are not subjected to glomerular trauma.

• c) Hemolysis in the bladder – Hemolysis does not cause dysmorphic RBCs; it leads to free hemoglobin or ghost cells.

• d) Sample contamination – Contamination (e.g., menstrual blood) would show normal (isomorphic) RBCs, not dysmorphic ones.

• Hyaline casts are composed almost entirely of uromodulin (Tamm-Horsfall protein), a glycoprotein secreted by the ascending loop of Henle and distal tubules.

• They are:

  • Transparent and pale under microscopy.

  • Non-pathologic in small numbers (common after exercise, dehydration, or fever).

  • The only type of cast that can be seen in healthy individuals.

Why Not the Other Options?

• a) Waxy cast → Made of degenerated protein (from compacted cellular casts), indicating chronic kidney disease.

• b) RBC cast → Contains red blood cells embedded in a protein matrix, diagnostic for glomerulonephritis.

• d) Fatty cast → Formed when lipid-laden renal tubular cells (oval fat bodies) or free fat droplets are incorporated into casts, seen in nephrotic syndrome.

• Clinitest is a reducing substance test for sugars (e.g., glucose, galactose), not protein.

• It uses Benedict’s copper reduction reaction and is unrelated to protein detection.

Confirmatory Protein Tests:

1. a) SSA (Sulfosalicylic acid) test – Precipitates all proteins (albumin, globulins, Bence Jones).

2. b) Bence Jones protein test – Detects monoclonal light chains (heat precipitation at 40–60°C).

3. c) Acetic acid test – Outdated but historically used to precipitate proteins.

Conclusion:
Clinitest (d) is the only option unrelated to protein confirmation.

• east cells (commonly Candida spp.) can resemble RBCs in size and shape, but they are distinguished by:

  • Budding (smaller daughter cells attached to larger parent cells).

  • Pseudohyphae (elongated, chain-like structures) in some cases.

• RBCs, in contrast, are uniform, smooth discs without budding or filamentous forms.

Why Not the Others?

• a) Refractivity – Both yeast and RBCs may show similar refractility under the microscope.

• b) Color – Yeast and RBCs can both appear pale/colorless in unstained urine.

• d) Size – Overlapping ranges (yeast: 3–10 µm; RBCs: 6–8 µm) make size unreliable for differentiation.

• Brownian movement refers to the random, jittery motion of small particles suspended in fluid due to collisions with water molecules.

• Bacteria (especially small cocci or rods) are tiny enough to exhibit this motion, appearing as small, shimmering dots under the microscope.

• Other options:

  • b) RBCs – Too large; they may show sedimentation or rouleaux formation, but not Brownian movement.

  • c) Crystals – Rigid structures; they do not move unless the fluid is flowing.

  • d) Yeast – Often larger (oval budding forms); may show slight movement but not the classic rapid jitter of Brownian motion.

• Squamous epithelial cells are commonly found in small numbers in the urine of healthy individuals, particularly in women. They originate from the urethra or vaginal lining and are usually a sign of normal shedding rather than pathology.

Why Not the Other Options?

• a) RBC casts – Always abnormal, indicating glomerular damage (e.g., glomerulonephritis).

• b) Broad casts – Seen in chronic kidney disease (CKD), formed in dilated tubules due to stasis.

• d) Oval fat bodies – Indicate lipiduria, associated with nephrotic syndrome or other renal disorders.

• Appearance:

  • Wrinkled (“thorn-apple” or rosette-like) shape with irregular edges.

  • Color variability: Yellow-brown, amber, or colorless.

  • Pleomorphism: Can appear as barrels, rhomboids, rosettes, or needles.

• Associated Conditions:

  • Gout, hyperuricemia, tumor lysis syndrome, acidic urine (pH <5.5).

Why Other Options Are Incorrect:

• a) Calcium carbonate → Small, colorless granules or dumbbell/spherical shapes (no wrinkling).

• c) Cholesterol crystals → Flat, transparent plates with notched corners (no color variability).

• d) Triple phosphate → “Coffin-lid” prisms (colorless, no wrinkling).

• Glucosuria (glucose in urine) most often occurs due to hyperglycemia from diabetes mellitus, where blood glucose exceeds the renal threshold (~180 mg/dL).

• The kidneys cannot reabsorb all filtered glucose, leading to spillage into urine.

Why Not the Others?

• a) Low renal threshold – Causes renal glycosuria (e.g., Fanconi syndrome), but this is rare compared to diabetes.

• b) Pancreatic cancer – May impair insulin production but is not a common cause of glucosuria.

• d) Starvation – Causes ketonuria, not glucosuria (blood glucose is typically low/normal).

• Glacial acetic acid lyses red blood cells (RBCs) by disrupting their membranes, helping to distinguish them from yeast or oil droplets, which remain intact.

• This is particularly useful when differentiating RBCs from yeast cells (which resemble RBCs but do not lyse in acetic acid).

Why Not the Others?

• a) Yeast – Resistant to acetic acid; remains visible under microscopy.

• c) Oil droplets – Unaffected by acetic acid (may still refract light).

• d) Creates RBCs – Incorrect; acetic acid destroys RBCs, not creates them.

Transitional epithelial cells and renal tubular epithelial cells (RTECs) are best distinguished by their size and nucleus-to-cytoplasm (N:C) ratio:

• Transitional epithelial cells:

  • Larger (vary from small to very large, depending on origin—bladder, ureter, or renal pelvis).

  • Lower N:C ratio (more cytoplasm relative to nucleus).

  • May have eccentric nuclei and occasionally bizarre shapes (e.g., caudate cells from the bladder).

• Renal tubular epithelial cells:

  • Smaller (about 1.5–2× the size of a WBC).

  • Higher N:C ratio (less cytoplasm, nucleus nearly fills the cell).

  • Often round/oval with granular cytoplasm (proximal tubule) or cuboidal (distal tubule).

Why Not the Other Options?

• a) Shape and location – Less definitive; both cell types can vary in shape.

• b) Granularity – Proximal RTECs are granular, but distal RTECs and transitional cells can be non-granular.

• d) Presence of lipids – Only relevant if RTECs are lipid-laden (oval fat bodies), which is situational.

• Cloudiness in refrigerated urine is most commonly caused by the precipitation of amorphous crystals (phosphates in alkaline urine or urates in acidic urine).

• These crystals form a fine, granular sediment when urine cools, creating a cloudy appearance.

Why Not the Others?

• a) Bacteria – Can cause cloudiness, but refrigeration typically inhibits bacterial growth (more likely in fresh, warm urine).

• b) Hyaline casts – Do not cause cloudiness (they are clear and require microscopy to detect).

• c) White blood cells (WBCs) – May cause turbidity, but refrigeration does not specifically increase their visibility

• Cystine crystals are hexagonal (six-sided), flat, and colorless under the microscope.

• They are pathognomonic for cystinuria, an inherited metabolic disorder causing defective renal reabsorption of cystine and other dibasic amino acids.

• Cystine crystals form in acidic urine and can lead to recurrent kidney stones.

Why Not the Other Options?

• a) Uric acid – Rhombic or rosette-shaped, associated with hyperuricemia (not inherited).

• c) Triple phosphate – Coffin-lid or prism-shaped, seen in UTIs with alkaline urine.

• d) Cholesterol – Rectangular plates with notched corners, rare in urine (associated with nephrotic syndrome).

• Leucine crystals appear as yellow-brown spheres with concentric circles (striations) under microscopy.

• They are pathognomonic for severe liver disease (e.g., cirrhosis, acute hepatic necrosis) or maple syrup urine disease (branched-chain amino acid disorder).

Why Not the Others?

• b) Bilirubin – Forms amorphous granules or needle-like crystals, not concentric spheres.

• c) Triple phosphate – Colorless “coffin-lid” prisms (alkaline urine, UTI-related).

• d) Ammonium biurate – Brown/yellow spiky spheres (“thorn apples”), seen in alkaline urine with UTI.

• Hyaline casts are the only casts considered physiologic in healthy individuals. They are composed purely of Tamm-Horsfall protein (uromodulin) and may appear transiently due to:

  • Dehydration

  • Strenuous exercise

  • Fever

• They are transparent, colorless, and have smooth edges under microscopy.

Why Not the Others?

• a) Fatty casts – Pathologic, seen in nephrotic syndrome (lipiduria).

• b) Waxy casts – Indicate chronic kidney disease or long-standing stasis.

• d) Granular casts – Suggest acute tubular injury (e.g., ATN) or cellular debris.

• Ghost cells are hemolyzed red blood cells (RBCs) that appear as faint, pale, empty membranes under the microscope.

• They form when RBCs are exposed to hypotonic (dilute) urine (low specific gravity) or highly acidic urine (pH <5.0), causing hemoglobin to leach out.

• Ghost cells are a classic sign of glomerular bleeding (e.g., glomerulonephritis), as they indicate RBCs have been in the urine long enough to degrade.

Why Not the Others?

• a) Clue cells – Vaginal squamous cells coated with bacteria (Gardnerella), seen in bacterial vaginosis (not urine sediment).

• c) Glitter cells – WBCs (neutrophils) with moving granules in dilute urine, associated with pyelonephritis.

• d) Oval fat bodies – Renal tubular cells filled with lipids, pathognomonic for nephrotic syndrome.

• Uric acid crystals often appear as rhombic plates or rosette-like clusters in acidic urine (pH <6.0).

• They are commonly seen in conditions like gout, tumor lysis syndrome, or dehydration.

Why Not the Others?

• a) Tyrosine – Fine, needle-like crystals (seen in liver disease or tyrosinemia).

• c) Calcium oxalate – Envelope-shaped (dihydrate) or dumbbell-shaped (monohydrate).

• d) Ammonium biurate – Brown/yellow spherical crystals with spikes (alkaline urine, UTI-related).

Conclusion:
Rhombic plates/rosettes (b) are classic for uric acid crystals, reflecting hyperuricemia or acidic urine.

• Trichomonas vaginalis is a pear-shaped (lemon/oval) flagellated protozoan that exhibits jerky, twitching motility under microscopy, a key diagnostic feature.

• It is a sexually transmitted parasite causing trichomoniasis and may appear in urine (though more common in vaginal/cervical samples).

• Best observed in fresh, warm urine (motility decreases as the sample cools).

Why Not the Others?

• b) Candida species → Yeast (budding cells/pseudohyphae), non-motile.

• c) Schistosoma haematobium → Helminth eggs (spine-tailed, seen in chronic infection), not motile in urine.

• d) Enterobius vermicularis → Pinworm eggs (asymmetrical, flattened side), found in perianal swabs,

• The sulfosalicylic acid (SSA) test is the most sensitive method for detecting all urine proteins, including albumin, globulins, and Bence Jones proteins.

  • It precipitates proteins, causing turbidity proportional to concentration.

• Unlike reagent strips (which primarily detect albumin), SSA catches non-albumin proteins (e.g., multiple myeloma).

Why Not the Others?

• b) Reagent strip – Only detects albumin (misses globulins/Bence Jones proteins).

• c) Heat and acetic acid test – Outdated; less specific than SSA.

• d) Biuret test – Measures total serum protein, not used for urine.

Conclusion:
For comprehensive protein detection, SSA (a) is the gold standard, especially for paraproteins.

• WBC casts (white blood cell casts) indicate inflammation in the renal tubules, which is the hallmark of AIN.

• Composition: Made of neutrophils or eosinophils (with Hansel’s or Wright’s stain) embedded in a protein matrix.

• Clinical Context:

  • AIN is often caused by drug hypersensitivity (e.g., NSAIDs, antibiotics) or infections.

  • Accompanied by pyuria, sterile urine culture, and possibly eosinophiluria (>5% eosinophils in urine).

Why Other Options Are Incorrect:

• a) Bacteria → Suggests UTI, not AIN (though infection can rarely cause AIN).

• c) RBC casts → Indicates glomerular inflammation (e.g., glomerulonephritis).

• d) Fatty casts → Seen in nephrotic syndrome (lipiduria), not AIN.

• Trichomonas vaginalis is a sexually transmitted protozoan that exhibits rapid, jerky motility in fresh urine or wet prep microscopy.

• Its movement is distinct from bacteria (non-motile or slow drifting) and spermatozoa (progressive, whip-like motion).

Why Not the Others?

• a) Yeast – Non-motile; may bud but lack directional movement.

• b) Bacteria – Show Brownian motion (tiny vibrations) but no purposeful motility.

• c) Spermatozoa – Motile but with linear, flagellar movement (only relevant in post-ejaculation samples).

• Starch granules (common contaminants from gloves or dust) exhibit a Maltese cross pattern under polarized light, resembling neutral fats but lacking clinical significance.

• They are round, irregularly sized, and easily distinguished from pathologic lipids (e.g., cholesterol esters in nephrotic syndrome).

Why Not the Others?

• a) Oil droplets – May show Maltese crosses but are rare contaminants (vs. starch’s ubiquity).

• b) Air bubbles – Non-birefringent and spherical.

• c) Glass shards – Irregular, sharp edges, no Maltese cross.

• RBC casts are pathognomonic for glomerulonephritis (GN) because they indicate bleeding at the glomerular level, where red blood cells are trapped in a protein matrix (Tamm-Horsfall mucoprotein) as they pass through damaged glomeruli.

• Their presence strongly suggests:

  • Acute glomerulonephritis (e.g., post-streptococcal GN)

  • IgA nephropathy

  • Lupus nephritis

  • Vasculitis-related GN

Why Not the Other Options?

• a) Bacteria → Suggests a urinary tract infection (UTI), not glomerular disease.

• c) Calcium oxalate crystals → Seen in acidic urine, associated with stones or ethylene glycol poisoning, not GN.

• d) Oval fat bodies → Indicate nephrotic syndrome (lipiduria due to heavy proteinuria), not GN.

• Ketonuria (ketones in urine) is most commonly caused by uncontrolled diabetes mellitus, particularly diabetic ketoacidosis (DKA), where insulin deficiency forces fat breakdown into ketones (acetoacetate, β-hydroxybutyrate, acetone).

• It is detected via urine dipstick (nitroprusside reaction) or blood ketone testing.

Why Not the Others?

• a) Liver cirrhosis – Causes metabolic disturbances but not ketonuria (liver synthesizes ketones but typically not in excess).

• c) Nephrotic syndrome – Leads to proteinuria/lipiduria (cholesterol crystals), not ketones.

• d) Urinary tract infection (UTI) – Causes bacteriuria/pyuria, unrelated to ketosis.

Conclusion:
Diabetes mellitus (b) is the classic cause of ketonuria, signaling urgent evaluation for DKA if paired with hyperglycemia.

• Yeast cells (e.g., Candida albicans) appear as small, ovoid, and often budding structures in urine sediment.

• They are common in diabetic patients, antibiotic use, or immunocompromised states and may indicate UTI or contamination (e.g., vaginal yeast).

Why Not the Others?

• b) Red blood cells (RBCs) – Smooth, non-budding discs (lyse in hypotonic solutions).

• c) White blood cells (WBCs) – Larger, granular, and may show nuclei (no budding).

• d) Renal tubular cells – Polygonal with eccentric nuclei, larger than yeast.

• Ictotest is the specific confirmatory test for bilirubin in urine, using a diazotization reaction to produce a blue/purple color.

• It is more sensitive and specific than reagent strips, which can yield false positives (e.g., phenazopyridine, chlorpromazine).

Why Not the Others?

• a) SSA test – Confirms protein (not bilirubin).

• b) Acetest – Detects ketones (not bilirubin).

• d) Biuret test – Measures total protein in serum, not urine bilirubin.

Conclusion:
Ictotest (c) is the gold standard to verify bilirubinuria, critical for diagnosing hepatobiliary obstruction or liver disease.

• Amorphous phosphates (white precipitate in alkaline urine) dissolve when the urine is acidified with acetic acid, confirming their identity.

• They are distinguished from amorphous urates (pink sediment in acidic urine), which dissolve with alkalization or warming.

Why Not the Others?

• a) New sample – Unnecessary; chemical dissolution is diagnostic.

• b) Normal saline dilution – Does not dissolve phosphates.

• d) Warm water – Dissolves amorphous urates, not phosphates.

• WBC casts (d) are a hallmark of pyelonephritis (kidney infection) because they indicate inflammation in the renal tubules.

• Cystitis (bladder infection) does not produce casts since inflammation is limited to the lower urinary tract.

Why Not the Others?

• a) WBCs – Present in both cystitis and pyelonephritis (nonspecific).

• b) RBCs – May occur in both but are not diagnostic.

• c) Bacteria – Can be seen in both conditions (not specific to kidney infection).

• Bacteria in urine are clinically significant when accompanied by white blood cells (WBCs), indicating an active urinary tract infection (UTI) rather than contamination.

• Pyuria (WBCs in urine) + bacteriuria = Strong evidence of true infection.

Why Not the Others?

• a) Nitrite is negative – Some UTIs (e.g., Enterococcus, Pseudomonas) do not produce nitrites, so bacteria may still be significant.

• b) Protein is positive – Nonspecific; proteinuria can occur without infection (e.g., nephrotic syndrome).

• c) Urine is dark yellow – Reflects dehydration or bilirubin, not infection.

Conclusion:
Bacteria + WBCs (d) confirm pathologic significance, warranting treatment for UTI.

• Urine reagent strips detect acetoacetic acid (and to a lesser extent acetone) via the nitroprusside reaction, which turns purple in the presence of ketones.

• β-hydroxybutyrate (BHB), the most abundant ketone in DKA, is not detected by standard strips.

Why Not the Others?

• a) Acetone – Volatilizes quickly and is weakly detected (only if urine is fresh).

• c) β-hydroxybutyrate – Requires blood ketone testing (e.g., serum BHB measurement).

• d) All of the above – False; strips miss BHB, the clinically dominant ketone in DKA.

• Calcium oxalate crystals are frequently found in normal, healthy individuals and are the most commonly observed crystals in routine urine analysis.

• They exist in two forms:

  • Calcium oxalate dihydrate (envelope-shaped, bipyramidal).

  • Calcium oxalate monohydrate (dumbbell or oval-shaped).

• Causes include:

  • Dietary factors (high oxalate foods like spinach, nuts, tea).

  • Mild dehydration.

  • Idiopathic (no underlying pathology).

Why Not the Others?

• a) Cystine → Always pathological, seen in cystinuria (a rare genetic disorder).

• b) Uric acid → Common in acidic urine (e.g., gout, dehydration, chemotherapy) but not typically “normal.”

• c) Triple phosphate (struvite) → Associated with UTIs caused by urease-producing bacteria (e.g., Proteus).

• The reagent strip test for blood detects the peroxidase-like activity of:

  • Hemoglobin (from lysed RBCs or hemolysis).

  • Myoglobin (from muscle breakdown, e.g., rhabdomyolysis).

• It cannot differentiate between the two, requiring clinical context (e.g., CK levels for myoglobinuria).

Why Not the Others?

• a) Free hemoglobin only – False; detects both hemoglobin and myoglobin.

• b) Intact RBCs only – False; intact RBCs must lyse to react (but microscopic exam confirms them).

• d) Only WBCs – False; WBCs are detected via leukocyte esterase, not blood pads.

• Definition: Glitter cells are neutrophils (white blood cells) that exhibit Brownian movement of granules when observed under the microscope.

• Appearance:

  • Granules inside the neutrophil shimmer or “glitter” due to movement in hypotonic urine.

  • Often seen in dilute or hypotonic urine (specific gravity <1.010).

• Clinical Significance:

  • Commonly associated with pyuria (urinary tract infection, UTI).

  • Not diagnostic of any specific condition but indicate active inflammation.

Why Other Options Are Incorrect:

• a) Highly refractile fat droplets → Seen in lipiduria (e.g., nephrotic syndrome), not glitter cells.

• b) RTE cell with granules → Renal tubular epithelial (RTE) cells may have coarse granules but do not “glitter.”

• d) Waxy cast with inclusions → Waxy casts are smooth, brittle, and lack granular movement.

Mucus threads can mimic casts (particularly hyaline casts) under the microscope, leading to a false interpretation of urinary casts. They appear as long, irregular, and wavy structures, which may be mistaken for pathological casts if not carefully distinguished.

Why not the others?

• a) Staining with Oil Red O – Used to identify lipid droplets or oval fat bodies, not casts. It does not typically interfere with cast interpretation.

• b) Use of polarized light – Helps differentiate crystals (e.g., uric acid, calcium oxalate) or lipids but does not usually cause false cast interpretation.

• c) Not centrifuging the specimen – May lead to missing casts due to low sensitivity, but it does not cause false-positive cast identification.

Waxy casts are characterized by:

• Serrated or notched edges

• Blunt or broken ends

• High refractility

• Often broader in size (especially in chronic renal failure)

These features suggest they have remained in the tubules for a longer time, indicating chronic kidney disease or severe tubular stasis.

Other options:

• a) Fatty – Contain lipid droplets; appear refractile but not serrated

• c) Hyaline – Smooth, transparent, and colorless

• d) Granular – Contain fine/coarse granules; not serrated

• Polarized light microscopy is particularly useful for distinguishing birefringent crystals like uric acid (multicolor interference patterns) from cystine (hexagonal, weakly birefringent).

• Uric acid crystals show strong birefringence (bright colors), while cystine crystals have a weak, uniform polarization effect.