Urinalysis

A urinalysis evaluates the physical and chemical composition of the urine.  It can provide
important diagnostic information about conditions of the urinary and genital tracts,
as well as a number of systemic diseases such as diabetes, liver disease, Cushing’s disease, etc. 
The urinalysis is an important part of the diagnostic evaluation for many diseases and is
also an important part of a thorough preventive medicine program. People often ask how
to collect a urine sample. We are happy to collect the sample for you, but if you are a do it
yourselfer, follow the instructions below.

Obtaining a Urine Sample
Urine collection with dogs usually presents few problems. If you’d like to collect urine at
home prior to the appointment, you can use a well rinsed, dry container that comes with a lid. 
Walk along side or behind your dog and when they prepare to urinate you can strategically
place the container so that he or she will urinate in to it. Wear disposable plastic gloves while
collecting urine. If possible, bring the urine to us immediately after collection. If it isn't feasible,
place the lid on the container and refrigerate it until you come in to see the vet. If you’d rather
leave the collecting to us, we are glad to do that. 
Cats on the other hand, make urine collection very interesting. If you’d like to collect urine
at home prior to the appointment, swing by Apple Lake and pick up a kitty urine collection
kit. Empty and wash your cat's litter box and rinse it well to eliminate all traces of detergent
or disinfectant. Dry it well and then place the special litter into the box. After your kitty
urinates, use the pipette to siphon the urine and then put the urine into the tube that came
with the kit. Place the cap securely on the tube and if possible, bring the sample in
immediately.  If that's not possible, refrigerate the sample until it’s time for your
appointment. The difficulty with cats is that they aren’t always ready to do what we wish. 
Many people opt to bring the kitty in for their checkup and then leave him or her with us
for the afternoon so that we can wait for results and clean up any messes that may occur. 
We then call you and you can pick up your friend when we are all done. 
Analyzing the Urine Sample
A complete urinalysis usually involves 3 steps:
  1. Checking and recording the color, turbidity (cloudiness), and specific gravity of the sample.
  2. Performing a chemical analysis using a multi-test dipstick.
  3. Placing a small portion of the sample into a centrifuge and then examining the sediment under the microscope.
Color/turbidity/specific gravity: Normal urine is amber-yellow in color and clear to
slightly cloudy. Concentrated urine is a darker yellow. Dilute urine may be colorless.
White blood cells may make the urine cloudy. Blood in the urine can give a red-brown tinge.
To determine the specific gravity, a drop of urine is placed into an instrument called a
Refractometer. In simplest terms, specific gravity indicates how well the kidneys are able to
concentrate the urine.  A healthy dog's specific gravity is >1.030 and a cat's is >to 1.040.   
Chemical analysis: Many chemical tests can be performed on a small quantity of
urine by using a dipstick. A dipstick is a piece of plastic to which pads of certain
chemical reagents have been attached. Each pad will test for a particular substance
in the urine. When the urine comes in contact with the reagents, a chemical reaction
occurs which changes the color of the pad based upon how much of the substance is
in the urine. The color of the pad is compared to a color chart and an approximate
amount of the substance can be determined.
The following substances are just a few of the chemicals tested during a routine urinalysis:
Urine pH – This number is a reading of how acidic or alkaline the urine is. On a pH scale of
1-14, 7 is considered neutral, meaning neither acid nor alkaline. A number less than 7 indicates
acidity, while a number greater than 7 indicates alkalinity. Most normal dogs and cats have a
urine pH of 5.5 to 7.0; however, some normal pets may have higher or lower values.
Protein – Healthy animals will usually not have any protein in their urine, although in
some cases small, trace amounts may be normal. The significance of any protein in
the urine is dependent upon the specific gravity of the sample. Small amounts of protein
are more significant in dilute or unconcentrated urine.
Glucose– If the glucose (sugar) in the blood is significantly higher than normal,
(for example, in diabetes) some of the excess will be found in the urine. Normal dog
and cat urine should be negative for glucose on a dipstick. There are several reasons
why glucose in the urine may falsely appear elevated, so it is important that any
suspicious test results be followed (or verified) by a blood glucose test.
Ketones – Ketones are substances formed in the body during the breakdown of lipids (fat).
When excess amounts of ketones are formed, their level rises in the blood, and in turn, the
urine. The condition of excess ketones in the urine is termed "ketonuria." Ketonuria may be
found in cases of starvation, in some diabetic patients, and in certain other diseases. 
Healthy dog and cat urine should be negative for ketones.
Bilirubin – Bilirubin is a pigment made by the liver from dead or dying red blood cells. Small
amounts of bilirubin may sometimes be found in the urine of healthy dogs. Bilirubin in
the urine of a cat is a concern and calls for further investigation. High amounts of bilirubin
in the urine can be a sign of liver disease, bile duct obstruction, or abnormal destruction
of red blood cells (hemolysis).
Blood – Healthy dogs and cats may have a few red blood cells in their urine, but greater
than normal amounts indicate a problem. Blood in the urine (hematuria) can be due to a
number of causes, including trauma, urinary tract infection, bladder stones, and blood
clotting problems.
Examining the Sediment
After a urine sample is centrifuged, the top liquid portion is poured off, and the heavier
particles in the bottom of the centrifuge tube are placed on a glass slide. Often, a drop
of stain is added. The slide is then examined under the microscope for several different
elements.
White blood cells – Urine sediment should be examined for the presence of white
blood cells. Larger than normal numbers of white blood cells may indicate inflammation
from a bladder or kidney infection. Bladder stones can also cause inflammation.
Bacteria – Urine sediment should be examined for the presence of bacteria. Large
amounts of bacteria usually indicate a bladder infection. Sometimes your veterinarian
may want to perform an additional test called a urine Culture and Sensitivity, which will
give information about the type of bacteria that are present and which antibiotic would
be most effective for treatment.
Crystals – Microscopic crystals, made up of minerals, can sometimes be found
in the urine. The most common types of crystals include struvite
(ammonium magnesium phosphate), calcium oxalate, and ammonium urate.
Under certain conditions crystals can clump together (precipitate) to form uroliths
(bladder stones). Not all cats and dogs with crystals in their urine will necessarily form
bladder stones. The type of crystal present, the pH of the urine, and other factors also
play a part.
Casts – Urine casts are small cylinder-shaped formations of cells and debris from
inside the tubules of the kidneys. The presence of casts and their composition can
give us more information about kidney function.
Summary
Lots of information! The urinalysis can provide us information not only about the
kidneys and bladder, but the liver, pancreas, and other organs. We hope that you have a
better understanding of the importance of this laboratory test. Pets coming in to see us for
urinary issues are often feeling pain and discomfort. We want to help them feel better as
quickly as possible. 

If you have any questions or concerns, please feel free to call us.