Urine Crystals

A urinalysis is a test of your urine. A urinalysis is used to detect and manage a wide range of disorders, such as urinary tract infections, kidney disease and diabetes.

A urinalysis involves checking the appearance, concentration and content of urine. Abnormal urinalysis results may point to a disease or illness.

Also Known as:  Urine Test, Urine Analysis , Urine CE, Urine C/E, UCE, Urinalysis

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Test Panel: Physical properties, Chemical Tests, Dipstick Tests, Microscopic Examination

Type of urine samples:

• Random sample:
  This is a diluted urine sample and may give an inaccurate interpretation of patient health. But is best to do microscopy to evaluate WBC or RBC.
• First Morning sample:
  This is the best sample for microscopy and urine analysis. This is the concentrated urine because of urine remained throughout the night in the urinary bladder. This will contains an increased concentration of analytes and cellular elements. Urine must have remained in the bladder for 8 hours is considered as the first-morning sample.
• Urine for sugar (Postprandial 2 hours):
  Postprandial 2 hours sample collected after 2 hours of high carbohydrate diet. 
• Midstream clean catch urine:
  This sample is needed for the culture and sensitivity of urinary infection. The patient is advised to clean the urethra, then discard the first few mL of urine. Now midstream of the urine is collected in the sterile container.
• 24 Hours of a urine sample
  • In this case, discard the first urine and note the time.
  • Now collect urine in the container for 24 hours and put the last sample in the container.
  • Refrigerate the sample.
  • This 24 hours samples are needed for measuring urea, creatinine, sodium, potassium, glucose, and catecholamines.
• Suprapubic collection of the urine sample:
  This is done in the patients who cannot be catheterized and the sample is needed for culture. This sample is collected by the needle.
• Catheter collection of urine:
  This is done by patients who are bedridden and can not urinate.
• Pediatric urine sample:
  In infants, special collection bags are made adherent around the urethra. Then urine is transferred to a container.

Urine Crystals:

Crystals can be found in the urine of healthy individuals. They may be caused by minor issues like a slight excess of protein or vitamin C. Many types of urine crystals are relatively harmless.

Normal Crystals
1. Uric acid Crystals: Urate crystals can form when you have high levels of uric acid in your blood. Your body produces uric acid when it breaks down purines — substances that are found naturally in your body.
2. Calcium Oxalate Crystals: Calcium oxalate crystals are found in individuals with acidic, neutral or alkaline urine. These crystals are colorless when viewed microscopically. There are two forms of the calcium oxalate crystal: the monohydrate and dihydrate form. The monohydrate calcium oxalate crystal is described as the “picket fence” form. These dumbbells shaped crystals are common in ethylene glycol toxicity. The dihydrate form is octahedral or “envelope” shaped.
3. Hippuric Crystals : Hippuric acid crystals are found in acid, neutral, or slightly alkaline urine. These colorless crystals are prisms, plates, or needle-like in shape. These crystals are often conglomerated into masses.
4. Calcium Phosphate Crystals : These are colorless crystals having shape like blunt ended needles or prisms, rosettes. These crystals are found in neutral to alkaline pH.
5. Triple Phosphate Crystals : Triple phosphate crystals form in alkaline urine and are composed of magnesium, ammonium and phosphate. These are rectangular in shape or similar with the coffin lid. These are sometimes associated with a bacterial urinary tract infection caused by urea splitting bacteria.
6. Calcium Carbonate Crystals : Calcium carbonate crystals are yellow to colorless dumbells or spheres with radial striations, found in alkaline urine. They are usually large crystals and can be readily observed at low magnification.
7. Ammonium Biurate Crystals: Ammonium urate (or biurate) crystals generally appear as brown or yellow-brown spherical bodies with irregular protrusions resembling “throny-apples”. These are found in alkaline urine.
9. Amorphus Crystals: Amorphous urates are found in acid urine. These crystals may appear pink on gross analysis and yellow microscopically. These crystals appear as granules in the urine sediment. Amorphous phosphates are found in alkaline urine. These granules are colorless microscopically.

Abnormal Crystals
1. Bilirubin Crystals:Bilirubin crystals are abnormal crystals in urine. They form from conjugated bilirubin and are needle-like to granular crystals that are yellow in color.They are frequently attached to the surface of cells. Bilirubin crystals are seen in several hepatic disorders.
2. Cholesterol Crystals : These appear as colorless rectangular plates with a notch in one or more corners and are found in acidic urine. The appearance of cholesterol is associated with the Nephrotic Syndrome.
3. Cysteine Crystals : Cystine crystals are flat colorless plates and have a characteristic hexagonal shape with equal or unequal sides. They occur in acidic urine that are associated with an inherited disorder. Presence of cystine crystals represents a proximal tubular defect in amino acid reabsorption.
4. Leucine Crystals : These are Yellowish-brown spheres with concentric circles with radial striations found in acidic/neutral urine. Leucine crystals may be seen in liver disorders in which amino acid metabolism is impaired.
5. Tyrosine Crystals: Tyrosine crystals appear as colorless/yellow fine needles in acidic/neutral urine. Tyrosine crystals may be seen in tyrosinemia and in certain liver disorders in which amino acid metabolism is impaired.
6. Sulfa Crystals: These are flat needles, sheaves of small needles or as spheroids. Often brown in color. The presence of sulfanomide crystals usually indicates administration of the drug and not necessarily a pathological condition.
7. Indinavir Crystals : Indinavir crystals can be observed readily in the urine sediment with the use of routine light microscopy. Approximately 20% of an oral indinavir dose is excreted in the urine during the ensuing 8 hours, half as the intact indinavir molecule and half as one or more of its seven known metabolites (three metabolites are closely related structurally to the parent compound).

Crystals in the acidic urine :

Crystals in alkaline urine :

Pathophysiology

1. There may be well-defined crystals or amorphous material in the urine sediment.
2. The presence of crystals in the urine is called Crystalluria.
3. When urine left at room temperature or refrigerated then urine becomes cloudy because of precipitation of crystals or amorphous material.
4. These crystals are important in case of kidney stones.
5. The stone formation may be without crystals in the urine or crystalluria may be without stone formation.
6. Some of the crystals indicate some metabolic disorders like cystinuria or sulfa drug.
7. Crystals are seen mostly in the concentrated urine.
8. Crystals are divided into :
   
   1. Normal  or abnormal
   2. In alkaline or acidic urine.
   3. Crystals found due to medication.
9. Crystals found in acidic urine has pH of <6.5 and in alkaline urine pH is >7.0.

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