1. Performing the Urinalysis
Laboratory Procedures

2. Analyzing the Urine Sample
A complete urinalysis usually involves 3 steps.
1. Checking and recording the physical characteristics of the urine
2. Performing a chemical analysis using a multi-test dipstick
3. Centrifuging a small portion of the sample and examining the sediment under a microscope

3. 1. Checking and recording the physical properties of the urine
Physical properties include:
Color
Transparency
Odor
Specific gravity
Volume

4. 2. Chemical Analysis
Many chemical tests can be performed on a small quantity of urine by using a dipstick
Dipstick is formed when certain chemical reagents have been attached to a piece of plastic.
Each pad on dipstick is designed to test for a particular substance in the urine.
When the urine comes in contacts with the reagents, a chemical reaction will cause a color change based on the amount of the substance in the urine.
Color is compared to chart, and approximate amount of substance in urine can be determined

5. Several brands of dipstick exist.

7. Chemical analysis
Certain drugs and medications may interfere with chemical tests.
Be sure to know any medications animal is currently receiving when performing a urinalysis.

8. Components on the Dipstick
Urine pH
Protein
Glucose
Ketones
Bilirubin
Urobilinogen
Blood
Nitrites

9. Urine pH Number of how acidic or alkaline the urine is
pH is affected by diet.
Plant diets can cause alkaline urine
High protein diets can cause acidic urine
Small animal pH is usually acidic
In general dog and cat urine pH is 6-7
Large animal urine is usually alkaline
Other factors may affect urine pH
Fever
Starvation
Certain drugs

10. Protein
Healthy animals will usually not have any protein in their urine although in some cases trace amounts can be found in concentrated dog and cat urine.
The urine protein level must be interpreted along with the Urine specific gravity.
Small amounts of protein are more significant in dilute or unconcentrated urine.
Protein may be lost in the urine due to glomerulopathies, inflammation, or hemorrhage.

12. Glucose
If the sugar in the blood is significantly higher than normal, some excess may be found in the urine.
Normal dog and cat urine should be negative for glucose.
In some cases if the urine has sat or is not ran immediately, false glucose readings may occur.

13. Ketones
Ketones are the substances formed in the body during the breakdown of lipids.
Normal pet urine should be negative for ketones
When excess amounts of ketones are formed, their levels rise in the blood and then are released in the urine.
Can cause CNS depression and acidosis
May result in ketonuria caused by:
Starvation
Diabetes

14. Bilirubin
Pigment made by the liver from dead or dying red blood cells.
Small amounts may sometimes be found in healthy dogs.
Dogs can conjugate bilirubin in their kidneys, so small amount may be insignificant.
Bilirubin found in cat urine is a concern and can be a sign of liver disease, bile duct obstruction, or hemolysis.

15. Urobilinogen Compound formed from bilirubin by intestinal tract.
Normal dogs and cats have small amounts of urobilinogen in their urine.
Results from dipstick are not considered very accurate in may be difficult to interpret.
Usually recorded as “normal” or “abnormal”.

16. Blood
Healthy pets may have a few red blood cells in their urine, but greater than normal amounts may indicate a problem.
Hematuria can be due to a number of causes:
Trauma
Urinary Tract Infection (UTI)
Bladder Stones
Blood Clotting Problems

17. Nitrites May be produced by the bacteria present in some infections
Test often shows a “false negative” and is considered inaccurate in pets.
However, if positive, should examine sediment closely for bacteria.

18. Examining Urine Sediment
After urine sediment is centrifuged (generally about 5 minutes), the top portion of the liquid is poured off and the sediment is resuspended and examined microsopically.
Indications for sediment exam include:
Provides additional information
A form of biopsy/cytology
Must be interpreted with other clinical data, including physical and chemical composition of the urine.

19. Urine Sediment Exam Procedure
1. Collect urine in a clean container
2. Throughly mix specimen and transfer 3-5 ml volume to a centrifuge tube
3. Centrifuge for 3-5 mins
4. Remove supernatant
5. Leave approximately 0.5 ml of supernatant
6. Resuspend urine sediment
7. Examine a stained or unstained sediment.

20. Potential Sediment Elements
White blood cells
Bacteria
Crystal
Casts

21. White blood cells
Larger than normal numbers of white blood cells may indicate inflammation from a bladder or kidney infection.
Remember the potential for contamination of WBC’s during sample collection.

22. Bacteria Sediment is examined for presence of bacteria
Small amounts may due to contamination, large amounts may indicate bladder infection (especially if sample is obtained via cystocentesis).
A urine culture and sensitivity may indicated with large amounts of bacteria.

24. Crystals Made up or minerals and can sometimes be found in the urine.
Under certain conditions, crystals can clump together to form bladder stones (uroliths).
The pH of the urine may influence the type of crystal development
Some animals and species are more predisposed to crystal and stone formation.

25. Common Crystal Types
Struvite
Calcium Oxalate
Ammonium Urate

26. Casts
Urine Casts are small cylinder-shaped formations of cells and debris from inside the tubules of the kidneys
Presence of casts and composition can indicate kidney function
Types of casts:
Hyaline
Granular
Waxy
Fatty
Cellular
Mixed
Bile stained