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.
Why Get Tested:
Urinalysis is often used:
- This is part of the routine workup of a patient.
- It can diagnose urinary tract infections.
- It can diagnose diabetes.
- Diagnose any abnormality of metabolism
When to get tested:
- When you have symptoms, such as abdominal pain, back pain, frequent or painful urination
- Sometimes as part of a health examination,
- Sometimes as part of a pregnancy check-up,
- Sometimes as part of a hospital admission,
- Sometimes as part of a pre-surgical work-up
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 storage and preservation (Precautions):
- To keep urine constituents intact, preservation of the urine is very important. If urine is not preserved that will leads to a change in the number of bacteria and chemicals.
- To prevent bacterial growth, immediately refrigerate the urine.
- Light sensitive chemicals are protected by keeping the urine in a colored bottle like amber plastic bottles.
- Precipitation of calcium and phosphate can be prevented by acidifying the urine.
- For to see the crystals, casts, RBC and white cells, freshly voided and concentrated urine is needed.
- Ideally, urine should be examined within one hour of collection.
- Sodium fluoride can be added to estimate 24 hours of glucose. It inhibits the growth of bacteria.
- 10 ml of HCl (6N) is added to the containers for the estimation of VMA.
Chemical Tests ( Dipstick test )
Normal Urine findings are :
|Appearance||Pale or yellow|
|Volume||1200 to 2000 ml/24 hours|
|pH||5 to 7|
|Specific gravity||1.001 to 1.035|
|Cast (hyaline)||0 to 5 / HPF|
|Red blood cells||≤ 3 / HPF|
|Blood||Negative Rarely 2 to 3 RBCs/HPF|
|White blood cells||≤2 to 5 HPFMale = 1 to 2 /HPFFemale = 0 to 5 /HPF|
|Squamous epithelial cells||≤ 15 to 20 / HPF|
|Glucose||Random sample = Negative24 hours sample = 1 to 15 mg/dL|
|Ketones||Urine = Negative|
|Bilirubin||Negative (o to 0.02 mg/dL)|
|Urobilinogen||NegativeRandom sample= <1 mg/dL2-hour sample = <1 mg /2 hours24- hours sample = 0.5 to 4.0 mg/dL|
|Albumin||10 to 100 mg /24 hours|
|Protein||Quantitative = negativeUrine 24 hours sample Adult male = 1 to 14 mg/dLAdult female = 3 to 10 mg/dLChild <10 years = 1 to 10 mg/dL|
|Calcium||Normal diet = 100 to 300 mg/24 hoursLow-calcium diet = 50 to 150 mg/24 hours(Another source = 0.3 g/24 hours)|
|Sodium chloride||average 10 g /24 hoursPatient with moderate to severe salt depletion = <10 mmol/L or <20 mmol/L /24 hours(Another source = 15.0 g/24 hours)|
|Sodium||Adult = 40 to 220 meq/24 hoursChild = 41 to 115 meq/24 hours|
|Potassium||Adult = 25 to 125 meq/ 24 hoursChild = 10 to 60 meq/24 hours(Another source = 3.3 g/24 hours)|
|Magnesium||75 to 150 mg/24 hours(Another source = 0.1 g/24 hours)|
|Creatinine||Male = 20 to 28 mg/Kg/24 hoursFemale = 15 to 21 mg/Kg/24 hours(Another source = 1.5 g/24 hours)|
|Urea nitrogen||5 to 15 g/24 hours|
|Nitrogen||7 to 20 g/24 hours|
|Urea||10 to 35 g/24 hours(Another source = 25.0 to 35.0 g/24 hours)|
|Uric acid||With normal diet = 250 to 750 mg/24 hoursWith purine-free diet = <400 mg/24 hoursWith high-purine diet = <1000 mg/24 hours(Another source = 0.4 to 1.0 g/24 hours)|
|Urobilinogen||0.2 to 4.0 mg/24 hours|
|Chloride||Adult = 110 to 250 meq/24 hoursChild <6 years = 15 to 40 meq/24 hoursChild 10 to 16 years = 64 to 176 meq/24 hours|
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