What's In The Urine? (Part II: Urinalysis)

In part one we discussed what important information you can get by paying attention to your dog's pee.

In the end, all you really need to be able to figure out is whether your dog needs to see a vet and how soon.

Your vet is much better at reading your dog's urine—after all, they’ve got the tools! Urinalysis is the technical term for a thorough examination of urine.

Veterinarians often recommend a urinalysis when presented with a dog with changes in their urinary or drinking habits (e.g., polyuria, polydipsia, dysuria, or urinary incontinence), when an owner has noticed a change in the characteristics (e.g., color) of a dog’s urine, if a dog seems to be “off” in any way, or as part of wellness screening.

If it sounds like veterinarians are willing to run a urinalysis at the drop of a hat… that’s actually a good thing!  

A urinalysis is inexpensive, noninvasive, and provides a wealth of information about a dog’s well-being.

But in order to get good information from a urinalysis, the sample needs to be fresh and uncontaminated.

To collect a sample, you can simply catch the urine in a clean container as your dog pees. It's not always as easy as it sounds, although we became quite skillful at collecting Jasmine's. Haven’t had to try with JD yet, but I bet it must be harder trying to catch it from a boy.

We usually collect a sample right in front of the vet's office, Jasmine loves to sniff around and make sure that all future visitors know she's been there.

It is important that you use a dry, clean container.

You can use a dirty old yogurt jar but don't be surprised if the urinalysis comes back with all kinds of results!

Don't laugh; this happens more frequently than you'd think!

A urine sample can also be collected by your veterinarian using a catheter or by cystocentesis (a needle inserted into the bladder).

This will ensure a fresh and uncontaminated sample but ouch! So far we’ve always gotten away with free catch samples with Jasmine. We weren't looking for infections though. When the vet is worried about the possibility of infection, the sterility of the sample is very important.

Now that your vet has the sample, they can evaluate the urine.

The first step is similar to what you might have observed yourself. The sample will be examined for color and cloudiness.

Next, the urine specific gravity (USG), the concentration of the urine, will be measured. USG tests the ability of the kidneys to concentrate urine.

Dilute urine could simply mean over-hydration, but it can also indicate kidney disease or other conditions that interfere with urine concentration.

Overly concentrated urine can be caused by dehydration or other problems.

A chemical analysis is a number of chemical tests performed using a dipstick (a specially coated test strip) or a special instrument.

The following tests are usually included in the chemical analysis:

Urine pH may be influenced by diet and an abnormally high or low pH can be behind the formation of bladder stones or crystals.

I remember stalking Jasmine with a collection jar and a pH test strip, checking her urine a couple of times a day, when urine acidity was a suspect for some of her issues at that time.

Glucose in urine is often a sign of diabetes mellitus or stress.

Protein levels are measured to determine whether there is kidney damage or inflammation in the urinary tract.

Ketones in the urine are usually associated with diabetes mellitus.

Excess Bilirubin can be a sign of liver disease.

Other chemical tests may be included in some types of urine dipsticks.

Finally, a centrifuge is used to separate sediment, which is then further evaluated under a microscope.

A higher than a normal number of red blood cells in urine can be caused by a number of issues, such as trauma, urinary tract infection, bladder stones or blood clotting problems.

The presence of white blood cells may indicate inflammation or infection.

Observing bacteria can indicate infection as long as the sample was taken using sterile technique. The urine can then be cultured to determine the type of bacteria present and which antibiotics should be most effective against them.

Crystals in the urine can be seen with bladder stones.

A special type of urinalysis can also be used to screen for Cushing's disease. Jasmine had that done recently. Her urine cortisol : creatinine ratio was measured. While this test is not conclusive for Cushing's disease, affected dogs will usually have abnormal results.

Because cortisol is a "stress" hormone, when testing for Cushing's, it is also important (next to having a clean sample) to get a sample where your dog will be calm. If you get a sample in or after a stressful situation, it will result in higher cortisol levels in the sample. 

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Like any other diagnostic tool, urinalysis is open to interpretation and further testing might be needed if the findings are inconclusive.

It is important that the results are viewed in light of a dog’s medical history, physical exam and other diagnostic tests.

Related articles:
Whats In The Urine? (Part I: What You Can Notice On Your Own)

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