Why does a vet check my cats urine?
Urine tests are very useful diagnostic tool for vets and humans. The composition, ph and amount all tell a story.
Cats in particular can get a number of nasty kidney and bladder diseases, looking at the urine allows the vet to gauge the health of various organs, not only the kidneys but the liver but also of general metabolism. This helps with coming up with a diagnostic of what is making the cat sick. An example of a common test is looking for sugar in the urine as a sign of diabetes.
Collecting a cat urine sample
Before you can test it, you have to collect your cat's urine. The process is relatively simple if your cat is willing to co-operate.
Essentially you replace your normal cat litter with a non absorbent material such as popping corn or oleophobic (non wettable litter) specialized cat litter. The litter box has to be cleaned before you do this so as to not contaminate the sample.
If you have more than one cat you need to keep the second cat out of the way so you can be sure the sample is from the right one.
Some cats don't take to change in their litter very willingly and will pee outside the box. For this reason you want to move the litter to a spot that can be closed in and preferably tiled such as a bathroom, so it's easy to clean. This ensures there are no attractive alternative spots to pee on and any accident can be cleaned up.
Here are a couple of videos on how to collect urine samples from a cat.
Another method is to clean the litter box and put some clean litter in the bottom. Over this, lay a layer of plastic wrap. Then hope that the cat will happily ignore the fact that you've tampered with his litter and pee on top of the plastic. You can then use a pipette or eye dropper to collect your sample.
some cat actually like to pee in crinkly plastic so rigging up some plastic in the litter box can be useful.
Vets will sometimes collect samples by catheterization, that is putting a tube to the bladder. Alternatives are just pressing on the bladder and catching the urine that is pushed out, or actually using a needle to get a sample, this is done if a sterile sample is required. Don't try this at home.
What is in urine anyway?
Urine is not an absolute fixed formula and there are some variations but roughly:
- 95% water. This can vary if the cat is not drinking much or if he's drinking a lot such as a cat with diabetes.
- 2% Urea. This is the main breakdown product of protein.
- .05% Ammonia and .003% Uric acid
- .1% Creatinine, This is a breakdown product of normal muscle cratine phosphate breakdown.
- There are various electrolytes and ions, the main ones are Sodium about .1% and Chloride about .6%
- .12% Phosphates
- .18% Sulphates
- AS well as the above there are a whole lot of marking chemicals the cats, particularly unfixed males, use to communicate.
How much urine does a cat void every day?
This varies on diet, and how much he's drinking. but you can expect a regular 10 pound cat to pee about 5-6 ounces a day. One formula I saw suggested 28ml per kilogram of cat per day. This comes to about 130 ml per day.
In clumping litter this would be 2-3 clumps per day. A cat can vary quite a lot from twice a day to 5 times.
It's sort of hard to estimate, particularly since cats are private and often don't like you to watch. If you have more than one cat then it's even trickier to estimate one cat's output. If your cat changes his habits all of a sudden or seems to be in pain or there is blood, or he suddenly decides to avoid the litter box, then there is a problem. If he stops completely drop everything and get him to a vet. If it's a blockage it could kill him fast.
Some urine test
Several companies including Patterson, Bayers and Siemens, produce dip-stick testing strips. If you've ever seen someone checking a swimming pool with strips that have coloured dots and comparing them to the label on the container, then you've seen a dip stick test.
Basically a urine test strip has a series of pads which each have different testing chemicals. When the test strip is put in the urine sample and removed, the dots change colours depending on what and how much there is of whatever that particular spot is made to test. The results can be compared to standard scales provided by the manufacturer.
Many tests including: blood, bilirubin, glucose, ketones, pH, protein specific gravity, and urobilinogen. Some dipsticks also include leukocytes and nitrite analyses.
For a good description of what each tests mean check out this Vetbook.org article. It's very readable.
These test strips are produced for animal as well as for human testing. Some of the dots are the same or very similar such as Ph or sugar and others vary somewhat. If you have gone to the doctor's and you were asked to pee in a bottle, this is probably the first test that was done.
It is quick, relatively inexpensive and can be very accurate.
What else can a vet see from your cat's urine?
The dip-stick method of testing your cat's urine can show possible infection but cannot differentiate between what bacteria are present. Sometimes the vet will order a culture. In that case a sample of urine will be placed in a suitable culture medium and allowed to grow. Vets will then assess what bacteria are present. This will help in deciding what specific antibiotic or other medication to prescribe.
Sometimes there are solids in the urine and these can indicate kidney stones, infections, or crystals. By centrifuging the urine solids can be concentrated and identified.
The colour and smell of the urine can also give clues. For example a dark or greenish urine can indicate liver or gallbladder issues. Pink could mean blood, and milky white could mean fat or pus in the urine.
This article is provided for information only. It is not meant as a replacement for veterinary care. If your kitty is sick see your vet.