Your dog’s lab tests (blood work, urine, and fecal tests) are an important part of keeping your canine companion healthy and happy. Integrative veterinarian Dr. Julie Buzby gives nine easy tips for getting the most out of your dog’s lab tests, including guidance on how to easily collect your dog’s stool and urine samples.

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. 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.
The health of your senior dog can change quickly, and early detection of these changes can improve prognosis if and when a health concern arises.
Generally, routine complete blood count (CBC), blood chemistry panel tests, and urinalysis can give your vet an early warning of oncoming disease processes. Liver disease, kidney failure, and other conditions may be evident in blood test results before your dog even begins showing signs of illness.
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 screening 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 benefits 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.
By knowing 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 you, your dog, and his or her veterinary team
- Avoid the cost of having to repeat tests

9 ways to get the most out of your dog’s lab tests
As much as I’d like to, a lot of times I’m not able to diagnose my patients with physical exams alone. More often than not, if a dog or cat is sick, we need to run some tests to figure out exactly what’s going on. On occasion, the test results are not as useful for diagnosis as we hoped. Use these tips to maximize the chance of your pup’s lab tests giving the most accurate answers possible.
1. Learn how to collect the best 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.” The same philosophy holds true for dogs, too. However, unless you’ve trained your dog to pee in a sterile cup on command, this may be a bit tricky. The tips below will can help.
4 tips for collecting your dog’s urine sample
- Collect your dog’s urine in 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, such as a pie tin. I’ve had some assistants that even collect urine samples using a (dedicated!) ladle.
- Let your dog start going a little bit first—Ideally, you don’t want the first few drops of urine. Instead, 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.
- Tape the container to a yardstick or ruler—For the ultra-private canine who won’t let you near 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 or her nervous. Just be careful to keep everything flat as to not spill your dog’s urine sample when you’re pulling it away.
- If possible, have the container lid handy when you collect the sample—It can be so frustrating to finally get a urine sample from a dog with a shy bladder, only to accidentally spill it on the way back inside.
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!

2. Know the best time of day to collect a dog’s urine sample.
Now that you have a plan for how to collect your dog’s urine for a sample, you may be wondering when to collect it. 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 or her kidneys work to conserve water in the bloodstream and concentrate the urine, which will be voided on the first morning potty break.
If you get a urine sample later in the day, it will likely be more dilute—which may make 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 urine sample allows your vet to get an idea of your dog’s concentrating ability, which is an indicator of kidney function.
Your vet may want a sterile sample collected in the office.
Sometimes, your vet may ask for a very fresh sample—even one that you or an assistant collect in the parking lot at the veterinary clinic. Freshness especially matters when evaluating crystals in the urine (crystalluria). Some types of crystals degrade quickly, and other types of crystals can form in stored urine.
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 a small needle into the bladder and removes some sterile urine. It may sound scary, but it’s actually quite common and safe. Also, it’s the only practical way to get a sterile urine sample, which is required for some advanced testing. Most dogs tolerate cystocentesis procedures very well.
If your dog is due for lab tests, ask your vet if he or she would like you to collect a first morning urine sample on the day of your appointment.
If possible, schedule a morning vet appointment or drop off samples early.
Typically, for routine urinalysis, fresher samples are going to provide the most accurate 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.
How long is a dog pee sample good for?
Your vet will give you guidance (or if you’re not sure, ask!) on what type of urine sample he or she wants. Usually, this is based on what specific urine values your vet is most interested in. Some crystals can form or degrade in under an hour. My general rule of thumb is to analyze the sample within 30 minutes.
Not all of my clients live close to the clinic, and I know life gets crazy, so this often results in collecting urine samples at the vet appointment.
3. Collect an adequate amount of urine for your dog’s urine sample.
“We don’t have enough urine to run the whole urinalysis. What part is most important to you?” Every vet has heard these words from the laboratory. Sometimes the urine sample we’ve been given consists of what appears to be three raindrops of pee.
To avoid this scenario, it’s better to give your vet plenty of urine in a sample than not enough. (By the way, this holds true for your dog’s fecal sample, too.)
As a general guideline, collect at least one tablespoon of your dog’s urine as a sample for routine urine testing.
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.)

4. Keep your dog’s urine sample in the refrigerator until your veterinary appointment.
Once you’ve collected your dog’s urine sample, what do you do with it? Keeping your dog’s urine samples cool (by putting them in the refrigerator) will help keep them fresher and yield better results.
Why I recommend refrigerating dog urine samples
Just like we refrigerate food to make it last longer, refrigerating lab samples helps to preserve them. 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.
5. Ask your vet about running dog urine tests and blood work at the same time.
Now that we have a solid understanding on how to collect your dog’s urine sample, let’s discuss why your vet may want to test urine and blood at the same time. 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 test to check for heartworm disease in dogs.) 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 in dogs.
One of the most important pieces of information I get from a urinalysis is the specific gravity, which is basically the concentration of the urine. Urine specific gravity can change with certain diseases or metabolic conditions—such as kidney disease, Cushing’s disease in dogs, etc. But it can also change with hydration. That’s one of the reasons it’s so important to test urine and blood simultaneously. It means your vet can compare the results, and distinguish between a normal change in a healthy dog and something that may be a problem.
6. Ask your vet if your dog should fast before the veterinary appointment.
With some exceptions, I typically recommend that my patients fast overnight before routine blood work. The exceptions to fasting include diabetic dogs who eat on a careful schedule, puppies, and routine screenings like a heartworm test. Why is fasting often recommended?
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.
If your dog eats before a blood test, it can make it more difficult for your vet to diagnose issues. That’s why your vet might recommend that you skip feeding your dog breakfast until after the vet appointment.

Also, 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. If you schedule an early morning appointment, this results in minimal disruption to your dog’s routine.
7. Check with your vet’s office to see if you need to bring a stool sample to your dog’s appointment.
No list of suggestions for getting the most out of your dog’s lab tests would be complete without a discussion about dog poop samples. Do you need to collect your dog’s stool sample? How does a vet collect a stool sample at the veterinary office? Let’s get to the bottom of these questions.
Stool samples can provide a veterinarian with a lot of information, from the presence of intestinal parasites, to certain GI diseases. I consider a fecal test for dogs to be an essential part of routine annual wellness care. I also recommend fecal testing for dogs that are experiencing signs of GI disease, such as diarrhea or vomiting.
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. While this works, it’s not really ideal (for sample size or for your dog). Instead, ask your vet if you need to bring a stool sample in to the appointment.
While many of my clients bring in a thimble-full of urine, on the other end of the spectrum, we typically get a plethora of fecal matter. And this is okay! No complaints! But if you’re wondering what size stool sample to bring, here is a rule of thumb:
For dogs, a stool sample the size of a walnut is enough (about a one to two inch sample). 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.

Should you refrigerate your dog’s stool sample?
Once you’ve collected your dog’s stool sample, what do you do with it?
Refrigerating the dog’s stool sample is probably less important than refrigerating urine, but it’s still helpful in a hospital setting, primarily because stool is full of bacteria. Refrigeration helps minimize degradation of the dog’s stool sample. Also, it 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.
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. The slight chance of altering the sample by keeping it at room temperature is simply not worth the risk of possibly contaminating human food. Room temperature fecal samples are fine for a few (three to five) hours. That’s why it’s ideal to try get the dog’s stool sample to your vet in a timely manner.
Remember, just like with urine samples, when it comes to your dog’s stool samples, the fresher the better!
8. Bring your dog’s urine or stool sample to your vet’s office in a disposable, clearly marked container.
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. She 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 glassware (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.
Tips for housing your dog’s urine or stool samples
While anything goes when it comes to containment devices for your dog’s stool or urine samples, here are some guidelines on how to bring a stool or urine sample to the vet:
- 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 done with it.
- Make sure the container is clean and dry. Any bags or containers should be clean and dry before you put your dog’s samples in them. Moisture and debris can contaminate the sample and interfere with interpretation of the results.
- 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 clean glass or plastic container is fine. Just make sure it is clean and dry and has a lid that seals tightly.
- For your dog’s stool sample, use any container that seals. 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.
- Label any containers with your name and your dog’s name. As much as we try to stay organized, you’ve probably noticed your vet’s office is very busy! 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 even 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.

9. Ask your vet for any special instructions prior to your dog’s appointment.
Trust me, I want diagnostic tests to provide answers for your dog as much as you do. To me, every patient is like a puzzle, and a non-diagnostic sample is like finding out you’re missing a puzzle piece after putting the other 999 pieces together.
Some tests have very specific requirements. We want to make sure these instructions are followed as precisely as possible to get the most accurate results. This is especially important for things like monitoring levels of medications (thyroid medications, phenobarbital, insulin, etc.) in the blood. We rely on blood results to know whether we’re prescribing your dog the right dose, and the timing of these tests in relation to when your dog got his or her medication can change things!
Some tests require fasting, some require feeding at specific times, etc. If there is any doubt about what tests your dog needs or what instructions you have for those tests, please ask! It’s as frustrating for your vet as it is for you if diagnostic tests have to be rescheduled over circumstances that could have been avoided. Communication is key!
Dog lab tests are another way to show your dog love
Finally, as your dog’s biggest advocate, you now have more tools in your toolkit to help your dog have a happy, successful veterinary visit. By working with your vet, understanding the importance of lab work, and knowing how to collect urine and fecal samples, you’re maximizing the chances that your dog’s lab tests will give you the most accurate answers. And that means you can rest assured that you are doing everything in your power to give your dog the happiest, healthiest possible.
What questions do you have about collecting samples for your dog’s lab tests?
Please comment below.
To collect a urine sample from my female Golden, I use a flat plastic Rubbermaid or similar container for sandwiches that has a lid. You can find them in them grocery stores and they’re inexpensive. I use grippers — the long pincher like tools older people often use to grab objects that are high or on the ground — to hold the container and that way I don’t have to be standing right next to my dog when she’s trying to go. It’s a lot easier for both of us and it keeps my hands clean.
Hi Mary,
This is great advice! Thank you for sharing your experience with our readers.