
Your Dog’s Lab Tests: Poop, Pee, & Blood, Oh My!
SUMMARY: Your dog’s lab tests are an important part of keeping your canine companion healthy and happy. Learn seven easy tips for getting the most out of your dog’s lab tests (including dog blood tests). Then get practical tips on how to collect your dog’s stool sample and how to collect your dog’s urine sample— all from Dr. Julie Buzby, integrative veterinarian and founder of ToeGrips® dog nail grips.
If you are sharing life with a senior dog, no doubt you and “lab work” are on a first-name basis. Screening lab tests, such as blood tests and urinalysis, are an important part of keeping your dog healthy. As dogs enter their senior years, they should visit their vet at least twice per year. (Remember, six months in dog years is equivalent to roughly three to four human years, and a lot can change in that amount of time.) Dog lab tests are recommended at these biannual wellness visits, especially if you’ve noticed a change in your dog’s appearance or behavior, or if your dog is on chronic medication.
Dog lab test results: a snapshot of what’s going on inside your dog’s body
While X-rays give your vet an internal snapshot of organ shape and size, lab tests provide an internal snapshot of organ function. From determining how well your dog is tolerating a long-term medication, to diagnosing disease and developing a treatment plan, routine preventative lab tests help your vet monitor your dog’s health and stay ahead of the curve. Even if your dog’s lab tests don’t point to red flags, your vet can compare new blood work results to previous lab tests (the baseline) to identify trends and address future concerns preemptively. I like to call this “plotting points on the graph” and it’s exceedingly valuable in caring for veterinary patients, who have no voice of their own.
The importance of getting good dog lab tests
You might be surprised to learn that you can play an active role in helping your veterinarian get high-quality diagnostic lab samples from your dog. Fear not, your part doesn’t involve the sight of blood or needles, just a little education, and good, old-fashioned common sense.
By being educated on what you can do to improve sample quality — including sample collection and delivery factors— you can:
- Provide your vet with the best samples to interpret
- Save time and frustration for your dog and his or her veterinary team
- Avoid the cost of having to repeat tests
7 ways to get the most out of your dog’s lab tests:
1. Run dog blood work and dog urine tests together
Evaluating your dog’s blood work in light of urinalysis results can help your vet get more breadth and depth of information compared to running blood work alone. This does not apply for every blood test (for example, a urinalysis would not be relevant when running a heartworm test), but it’s beneficial to check your dog’s blood work and urine at the same time to evaluate kidney function, confirm certain metabolic disorders, and screen for urinary tract infection.
2. Collect a urine sample first thing in the morning
A first morning urine sample is generally the most concentrated sample of the day since dogs don’t typically drink overnight (If your dog often drinks overnight, that’s worth discussing with your vet). While a dog is sleeping, his kidneys work to conserve water in the bloodstream and concentrate his urine, which will be voided on the first morning walk. If you get a sample later in the day, it will likely be more dilute— which makes it harder for your vet to interpret. Might your dog have a problem with his kidneys, or did he just drink a lot of water that day? Obtaining that first morning sample allows your vet to get an idea of your dog’s concentrating ability, which is an indicator of kidney function.

Ask your vet if he or she wants the freshest sample
Sometimes, your vet may ask for a very fresh sample — even one that you collect in their parking lot. Freshness matters the most when evaluating crystals in the urine (crystalluria). Crystals degrade quickly, and test results can be inaccurate if the urine is more than 20 minutes old.
Your vet may also choose to collect a sterile urine sample in-house through a process called cystocentesis. It’s basically like an amniocentesis for the bladder — your vet puts the needle into the bladder and removes some sterile urine. It sounds ghastly, but it’s actually quite common and safe (and the only practical way to get a sterile urine sample, which is required for some advanced testing).
In general, fresher is better
Typically, fresher samples are going to provide better results. I recommend that my clients collect their dog’s first morning urine sample, put the urine in the refrigerator (keep reading to find out why), and schedule morning veterinary appointments to run lab tests, whenever possible. If your vet doesn’t need to see your dog — and you’re just dropping off samples — then I definitely recommend dropping off the samples as early as possible in the morning.
3. For your dog’s blood work, a “fasted” sample may be optimal
Although this doesn’t apply for something like a simple heartworm test, for diabetic dogs who eat on a careful schedule, or for puppies, I recommend that my patients fast overnight before lab work. This is somewhat controversial in veterinary medicine, with some arguing that it is unnecessary, but I am convinced the potential benefits (clearer diagnostic results) outweigh the downside (your dog having a delayed breakfast). I’m sure your food-motivated dog would disagree, but I’m holding my ground. 🙂
If your dog eats before blood work, it can make it harder for your vet to diagnose a concern
When your dog digests his or her food, some of the emulsified (digested) fat can be temporarily absorbed into the bloodstream. This condition is known as lipemia. A lipemic blood sample (one that contains fat) tends to cause hemolysis (breakdown of the red blood cells), which changes the color of the blood. This color change can then interfere with the way the lab machinery analyzes the results. (Granted, some ultra-expensive machines in veterinary laboratories can compensate for the color change and still give accurate results.) But the bottom line is that if your dog eats before a blood test, it can make it more difficult for your vet to diagnose issues.
Skip feeding your dog breakfast until after the vet appointment
Unless instructed otherwise, there is no reason to restrict water before the appointment for lab work— just don’t feed your dog breakfast. You can then feed your dog as soon as the appointment is finished (even in the parking lot). If you schedule an early morning appointment, this results in minimal disruption to your dog’s routine.

Ask your vet for any specific instructions prior to the appointment
As always, you should go with your vet’s recommendations. When you schedule an appointment for your dog’s blood work, urinalysis, or any dog lab tests, just ask, “Does the doctor want me to fast my dog, or follow any other specific instructions?”
4. Refrigerate any samples you collect from your dog (urine or stool)
Keeping your dog’s urine samples cool (by putting them in the refrigerator) will help keep them fresher and yield better results. Just like we refrigerate food to make it last longer, refrigerating lab samples helps to preserve them.
Dog urine samples and refrigeration
I recommend that clients refrigerate dog urine samples from the time they collect them until they bring them to the office. If your vet sends urine to an outside laboratory, he or she will surely refrigerate your dog’s urine sample until the shipping service picks it up. Refrigeration is important because a change in urine pH, proliferation of bacteria, and cellular degeneration can all affect the results. Refrigeration helps to slow these changes.
Refrigerating dog stool samples at home is not recommended
Refrigerating the dog’s stool sample is probably less important than refrigerating urine, but it’s still helpful, primarily because stool is full of bacteria. Refrigeration helps minimize degradation of the dog’s stool sample, and preserves some of the structures we look for when running fecal analysis testing. That’s why, in our clinic, we refrigerate dog stool samples that are being sent out to the lab. However, we have a refrigerator dedicated to storing the exciting specimens we handle in veterinary medicine, and it’s against federal regulations for human food to be stored in the same fridge.
Here’s the poop:
If you’re collecting a stool sample from your dog, we generally do not recommend that you put your dog’s stool sample in your refrigerator at home.
Dogs can commonly carry parasites that are transmissible to humans via a fecal-oral route. If you put your dog’s stool sample in your refrigerator, there’s a (slight) chance that it could accidentally contaminate other food. It’s just not worth the risk, in my opinion. Room temperature fecal samples are fine for a few (three to five) hours, so just try to get the dog’s stool sample to your vet in a timely manner.
5. Understand how much dog urine or feces you need to collect
It’s better to give your vet too much of a dog stool or urine sample than not enough, but here’s what your vet really needs:
A dog’s urine sample — collect at least one tablespoon
“We don’t have enough urine to run the whole urinalysis. What part is most important to you?” Every vet is familiar with these words. Sometimes the urine sample we’ve been given consists of what appears to be three raindrops of pee. So while more is always better when it comes to urine, just a tablespoon or two is all your vet really needs to run a urinalysis. (There are 16 tablespoons in a cup if that helps you visualize the volume.)

A dog’s stool sample — bring in a sample about the size of a walnut
On the other end of the spectrum, clients tend to bring us a plethora of fecal matter. And this is okay! No complaints! But a stool sample the size of a walnut is enough. For small dogs, this may be their full sample from the morning walk. From larger dogs, just one sizable fecal ball is all we need.
If you go to the vet sample-less and they need a dog stool sample for testing, your vet may insert a gloved finger or “fecal loop” instrument into your dog’s rectum to collect a stool sample — but that’s not really ideal (for sample size or for your dog).
6. How to collect a urine sample from your dog
You’ve probably seen the signs in your own doctor’s office’s bathroom asking for a “clean, midstream urine sample.” But unless you’ve trained your dog to pee in a sterile cup on command, this may be a bit tricky. Here are a few tips:
Let your dog start going a little bit first
Ideally, you don’t want the first few drops. Let your dog begin urinating for a second before you start collecting (this is what “midstream” means). A midstream urine sample is theoretically a “cleaner” sample because the first flow should help clean the outside of your dog’s external urinary tract.
Be quick and decisive
Some dogs are very private, and don’t want you lingering around their hind end. For these dogs, you typically have one chance to collect the urine sample. Once they figure out that you’re trying to interfere with their private business, they’re done.
Use a flat container with a low lip
A deep container is harder to get under your dog. Try using a flat container with a low lip, like a Tupperware lid (for smaller dogs) or perhaps a pie tin (for bigger dogs).
Tape the container to a yardstick or ruler
For the ultra-private canine who won’t let you near him for sample collection, you can use duct tape (or similar) to tape the container to a yardstick or ruler. This way you can get the container where it needs to be without you being right on top of your dog and making him nervous. Just be careful to keep everything flat as to not spill your dog’s urine sample when you’re pulling it away. Of course, it also helps if you can keep leaves, grass, and your dog’s muddy paws out of the urine sample, too. This can be easier said than done!
7. Choose the right container for your dog’s urine or stool sample
I’ve seen urine and stool samples delivered to the vet’s office in everything from food take-out boxes to family valuables. And if you think I’m exaggerating, I present the evidence shared by my friend and colleague, Kelsey Carpenter who started a social media project dedicated to capturing the humor in the containment devices which clients use to transfer their dogs’ stool or urine samples to the vet hospital. Here are a few of my favorites:
Fine china (for special occasions)…

…salsa jars (mild and chunky)…

…and even Panera (special delivery).

Did these make you smile? For more photos, please check out Kelsey’s Facebook page, @VET TECH KELSEY.
Tips for housing your dog’s urine or stool samples
While anything goes when it comes to containment devices, here are some guidelines for what you should use to house your dog’s stool or urine samples:
Use something disposable
Trust me — if your dog’s urine or stool was in it, you really don’t want it back. Use something that your vet can throw away once they’re done with it.
Make sure it’s clean and dry
Any bags or containers should be clean and dry before you put your dog’s samples in them.
Ask your vet about a free container for collecting your dog’s urine or stool sample
Your veterinarian should be able to provide you complimentary supplies for sample collection, which are provided to us free from our laboratory. These containers are designed to be tidy and efficient. If your vet doesn’t readily offer a container, feel free to ask if they have them available.
Use glass or plastic for your dog’s urine sample
For collecting your dog’s urine sample, any glass or plastic container is fine. Just make sure it is clean and dry and has a lid that seals tightly.
Use any container that seals for your dog’s stool sample
For feces, really any type of container is acceptable. You can use a Ziploc bag or any sort of disposable plastic container. Again, just make sure it seals closed and please never use a container that you want back because we would feel obligated to wash it out before returning it 🙂 .
Label any containers with your name and your dog’s name
Containers are sometimes taken to the lab by the front desk staff and left for the lab technicians without any explanation. Labeling helps ensure that the tech doesn’t mix up your dog’s urine or stool sample with a sample from someone else’s dog or accidentally dispose of it. Use a permanent marker to write your dog’s name and your full name on every container you give your vet.
Conclusion: on lab tests and loving your dog

Our mission is to help people help their dogs. Helping your veterinarian get the best lab samples for lab testing possible is an unorthodox but legitimate part of that mission! Feel free to comment below with questions, share your own stories about your dog’s lab tests, or offer tips on how you’ve collected your dog’s stool sample or urine sample. And don’t forget to listen to the podcast to hear me talk about improving dog lab tests — and other topics that can help you keep your senior dog healthy and happy.
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