By: Lou Grace T. Manalili, RMT, DVM
Two general standpoints may be considered in the routine urinalysis. First is for the management and diagnosis of renal or urinary tract disease and second, the detection of systemic or metabolic diseases indirectly to the kidney.
Routine urinalysis is composed of four parts:
- SPECIMEN EVALUATION – this implies specimen acceptability. Proper specimen labeling, proper use of preservative and any transportation delays in getting the specimen to the laboratory are some considerations to consider.
- PHYSICAL TESTS – these include color, odor, volume, osmolality and specific gravity of urine.
- Color- urochrome is a pigment responsible for the normal color of urine that varies from pale yellow to amber and this is also due to small amounts of pigments uroerythrin and urobilins. Any abnormalities in color maybe a cause of a renal disease or just a physiologic cause from food intake or medicine.
- Odor – faint aromatic scent is normal, a change in odor like foul or ammoniacal indicates bacterial contamination.
- Volume – adult daily average volume of urine ranges from 1.2 Liters to 1.5 Liters.
- Osmolality –500 to 850 mOsm/kg of urine will be produced by an individual in a regular diet taking 8 to 10 glasses of water a day.
- Specific gravity – this varies from 1.016 to 1.022 during a 24-hour period.
- CHEMICAL EVALUATIONS
- pH in urine – this is an indication of the capability of the kidney to sustain normal hydrogen ion concentration in plasma and extracellular fluid.
- Protein – occurrence of this in urine may arise after a tough exercise or dehydration or patients with urinary tract infection, hemorrhage or with fever.
- Glucose – in a typical urine sample, glucose is absent but this maybe present in the urine if blood glucose level exceeds 180 to 200 mg/dl.
- SEDIMENT EXAMINATION – this is done through the use of a microscope and usually for the detection of diseases of the kidney. Presence of casts, increase amount of pus cells, blood cells or bacteria indicate urinary tract infection and/or a renal disease.
Routine urinalysis also has two major components: the macroscopic and the microscopic testing. Available reagent strips are being used for the macroscopic examination that includes the chemical and physical tests of urine.
- Steps for Macroscopic Routine Urinalysis
- Examine and evaluate urine specimen. Properly label, indicate name, age, gender of owner and record time received, volume and color.
- Pour 10-15ml of urine in a centrifuge tube and take note on the report if the volume is less than the required volume.
- Determine transparency or clarity as to clear, slightly turbid or turbid.
- Determine specific gravity, pH, glucose and protein with the use of reagent strips. Compare strips to color chart and record results.
- Prepare urine specimen for microscopic test.
- Steps for Microscopic Routine Urinalysis
- Centrifuge urine sample of 10-15ml in a tube for about 5 minutes.
- After centrifugation, carefully tilt the tube bottoms up to separate sediments from the supernatant. Save the supernatant for possible retesting.
- Gently suspend the sediment on a glass slide and place a cover slip on top of it.
- Examine under low power objective in at least 10 low power fields sediments with low refractive index like, epithelial cells, mucus threads, urates, casts, crystals and bacteria. Report as few, moderate or many.
- Red blood cells and pus cells are identified and counted under a high power objective in at least 10 high power fields. Report as cell/hpf.
- Comment and take note for presence of large amount of crystals, bacteria, yeast or any microorganism. Perform confirmatory test if needed.
Review results, make a report on the test then affix your signature on the form to determine examiner.