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 – (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
Urobilinogen Ehrlich units

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