While many diagnostic tests require that a patient be physically present, it is not uncommon for a veterinarian to ask pet owners to collect samples like urine or stool at home. While the request seems simple enough, we often forget that people don’t necessarily know how to go about it or what we really do with the sample once we have it.
Urine is essentially finely filtered blood, making it informative about a variety of medical problems. It should be clean and sterile in a normal animal. Blood cells and bacteria might alert us to a lower urinary tract infection. Microscopic crystals could raise suspicion of larger bladder stones. Sugar makes us worry about diabetes. Poorly concentrated urine could suggest kidney disease or hormonal disorders. But these results can easily be thrown off by sample contamination, making proper collection important.
Urine should always be collected in a clean, dry container and promptly sealed. Usually that means some kind of glass or plastic food container, but if the test is planned in advance, your vet may be able to provide a sterile cup so you don’t have to ruin your kitchen supplies. More is always better, but, in most cases, a tablespoon or so should be enough to run the test. Remember, the longer it sits, the more it can affect the results. Cells break down, bacteria multiply, and crystals can form. Urine should be submitted as soon as possible after collection and refrigerated if it will be more than a few hours.
Actually collecting the sample can be tricky. Because urine is so sensitive to contamination, it generally shouldn’t be sucked or squeegeed off the floor, nor can it be sopped up with a towel and wrung out. And yellow snow is not going to work. It needs to be a clean catch.
If you have a male dog that lifts his leg, it may be simple enough to intercept the stream with the container. Female dogs often squat low enough that your container may not even fit in the limited ground clearance, in which case it may be better to use the container’s lid. But if all else fails, you can always have veterinary staff collect it for you. We’ve all gotten pretty good at it, but make sure your dog doesn’t pee on the way in.
Cats are another story entirely, since they pee when and where they want. You might be able to get them to urinate in an empty litter box—they even sell non-absorbent plastic litter pellets for this purpose—but the box needs to be extremely clean. Because it is so difficult, most cat urine is ultimately collected at the vet, often by obtaining it directly from the bladder with a needle. I promise it’s not as bad as it sounds.
That brings us to poop. A stool sample is likely to be recommended in any pet with gastrointestinal symptoms, like diarrhea or vomiting, and is primarily intended to screen for parasites. In simplest terms, this is done by mixing the stool up with sugar water and seeing if any parasite eggs float to the top, a process which smells as great as it sounds.
Happily, stool samples are much more forgiving and can be used in almost any condition. Stool is not inherently clean or sterile. It contains so much extra junk that contamination isn’t a huge problem. If some grass or a bit of cat litter is mixed up in the sample, it won’t matter. But some parasites are less resilient than others, and samples should still be reasonably clean and fresh.
Poop can be submitted in pretty much any container—any old plastic bag will do fine. While small samples can be run, larger samples give us a better shot at finding something. If it’s really loose you might need to work a bit to scoop it up. I know it’s gross, but just think about what we have to do with it later.
Dr. Mike Fietz is a small animal veterinarian at Georgetown Veterinary Hospital. He received his veterinary degree from Cornell University in 2003, and has lived in Charlottesville since.