Unit #5A – Clinical Laboratory Testing - Urinalysis

1. Unit #5A – Clinical Laboratory Testing - Urinalysis Cecile Sanders, M.Ed., MLS(ASCP)

2. Unit #5A – Clinical Laboratory Testing - Urinalysis • Urinary system is an excretory system • Renal System (reproduced with permission from Baylor College of Medicine)

3. Unit #5A – Clinical Laboratory Testing - Urinalysis • Collection and Preservation of Urine • Urinalysis performed for two purposes • Check for metabolic by-products • Observe physical, chemical and microscopic characteristics • Types of Specimens • First morning urine specimen is preferred • Mid-stream (urine caught from middle of urine stream) • Clean catch (patient must cleanse urethral opening prior to urinating and catching urine)

4. Unit #5A – Clinical Laboratory Testing - Urinalysis • Handling and preserving specimens • Examine within 1 hour of collection OR • Refrigerate at 4-6° C for up to 8 hours • Preservatives (least ideal) • When urine sits at room temperature • Bacteria multiply • Glucose decreases • Casts and cellular elements decompose

5. Unit #5A – Clinical Laboratory Testing - Urinalysis • Color of urine • Yellow – dilute urine is usually lighter in color; concentrated urine is usually dark • Red – may have blood present • Brown/black – may be associated with melanoma • Yellow-brown or green-brown – may be associated with liver conditions such as hepatitis or cirrhosis

6. Unit #5A – Clinical Laboratory Testing - Urinalysis • Light yellow, brown, and dark yellow urines

7. Unit #5A – Clinical Laboratory Testing - Urinalysis • Transparency • Urine normally transparent • Turbid – may be associated with crystals that settle out of urine at room or refrigerator temperature • Cloudy – may be associated with UTI OR crystals

8. Unit #5A – Clinical Laboratory Testing - Urinalysis • Specific gravity is the ratio of the weight of a given volume of the solution (urine) to the weight of an equal volume of water • Indicates concentrations of dissolved chemicals such as glucose, salts, etc. • The result of the kidneys’ ability to concentrate urine • Normal values – 1.005-1.030 (Ave = 1.015) • Usually measured by dip stick or refractometer

9. Unit #5A – Clinical Laboratory Testing - Urinalysis • Chemical Examination of Urine • Reagent strips • Test pads are for pH, protein, glucose, ketone, bilirubin, blood, urobilinogen, specific gravity, leukocytes and bacteria • Used only once and discarded • Performing the chemical tests by reagent strip • Perform within 1 hour after collection OR • Allow refrigerated specimens to return to room temperature • Dip strip in fresh urine and compare color of pads to the color chart after appropriate time period • Instruments are available which detect color changes electronically

10. Unit #5A – Clinical Laboratory Testing - Urinalysis • Urine Multistix – reading dipstick results manually; colors are matched to those on the bottle label; timing is critical for each pad.

11. Unit #5A – Clinical Laboratory Testing - Urinalysis Multistix

12. Unit #5A – Clinical Laboratory Testing - Urinalysis • Bayer Clinitek automatically reads a urine dipstick and prints out results

13. Unit #5A – Clinical Laboratory Testing - Urinalysis • Principle of chemical tests • pH measures degree of acidity or alkalinity of urine • Presence of protein (proteinuria) is an important indicator of renal disease, such as pyleonephritis • Presence of glucose (glycosuria) indicates that the blood glucose level has exceeded the renal threshold, such as in diabetes

14. Unit #5A – Clinical Laboratory Testing - Urinalysis • Ketones are excreted when the body metabolizes fats incompletely (ketonuria), such as in diabetes • Bilirubin is a byproduct of the breakdown of hemoglobin. Its presence may be an indication of liver disease, bile duct obstruction or hepatitis • Presence of blood may indicate infection, trauma to the urinary tract or bleeding in the kidneys • Urobilinogen is a degradation product of bilirubin formed by intestinal bacteria. It may be increased in hepatic disease or hemolytic disease

15. Unit #5A – Clinical Laboratory Testing - Urinalysis • Nitrite formed by gram negative bacteria converting urinary nitrate to nitrite. Presence of nitrites in fresh urine can indicate infection – in an old urine, nitrites can be positive without an infection • Leukocytes usually indicate infection • Specific gravity reflects kidney's ability to concentrate urine • Normal values • Negative results for glucose, ketones, bilirubin, nitrites, leukocyte esterase and blood • Protein negative or trace • pH 5.5-8.0 • Urobilinogen 0.2-1.0 Ehrlich units

16. Unit #5A – Clinical Laboratory Testing - Urinalysis • Resources • Basic Clinical Laboratory Techniques, Estridge and Reynolds, Thomson/Delmar Learning, Fifth Edition, 2008