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Ever wonder what happens when a sample is sent to UF’s Diagnostic Laboratory? Dr. Michael Dark, clinical associate professor and director of CVM’s veterinary diagnostic labs, takes listeners behind the scenes of a diagnostic laboratory to explore the journey of a sample from collection to final result. He’ll detail the process, people and technology that ensure every specimen is accurately processed, analyzed and interpreted, turning samples into actionable information that helps clinicians and clients make informed decisions and support better patient care. Transcript: DANA HILL: Welcome to Animal Airwaves Live here on WUFT-FM, our weekly hour long show devoted to the discussion of the health and welfare of animals. So happy you could tune in today on this Friday, September 4, 2026. And happy to welcome to the program my guest from the University of Florida College of Veterinary Medicine, Dr. Michael Dark. And the topic today, Tracking the Tube: A Day in the Life of a Diagnostic Sample, From Collection to Conclusion. DH: That includes a lot of different kinds of samples and we’re going to find out what those are today. So, first of all, let me welcome you back to the program. Dr. Dark, really glad that you could be here. MICHAEL DARK: Thanks, Dana. Thanks for having me. DH: When we think about samples, we think perhaps about the – what happens when we take our pets to the veterinarian’s office and the veterinarian will do an exam, look over our pet, you know, look inside their mouths and maybe, you know, touch their tummies and that sort of thing. And then there might be an occasion which the veterinarian says, okay, we’re gonna just take the pet to the back and we’re gonna get a sample or two. This happens in a pretty good number of veterinary visits, would you say? MD: Yeah, yeah, I’d say a lot of visits end up getting samples, whether it’s kind of routine visits, but especially in animals who have some kind of problem where they’re getting worked up. DH: And would you say then that these samples for, you know, I mean, for in, well, visits and in visits where we suspect there may be a problem. And with these different kinds of samples, though, we’re talking about everything from, I don’t know, fluids like urine or something like that, to blood to maybe even tissue samples. MD: Yeah, and a lot of that depends on exactly what’s going on with the patient. But it’s pretty common to look at blood to try and get an idea about a lot of different conditions. It’s not uncommon for vets to collect stool samples to check for parasites. And then if there’s a mass or an issue, then tissue samples can tell you quite a bit about what’s going on. Because we can look at those under the microscope and get a better idea of what the disease is. DH: Then maybe let’s kind of start with some of the types of samples then, broadly speaking, that veterinarians might be looking at and what circumstances might lead them to collect these samples. You mentioned blood. That’s got to be one of the more common samples, correct? MD: It is, yeah. And for instance, a test a lot of people are familiar with heartworm testing in dogs is a huge thing, especially here in Florida, where we have mosquitoes nearly year round. Veterinarians will take blood samples a lot of times now, heartworm testing can be done in clinic, so they can take a sample of blood and apply it to a kit that’s a little like the Covid test kits a lot of us used during the pandemic to check for Covid. Instead of nasal swab, you put a drop of blood on and it will give you an idea about whether the animal is infected with heartworm or not. And so that’s a rapid test that can be done quickly in the clinic and a result can come back. DH: If you don’t mind me kind of getting into something complicated right off the bat. How are these sorts of tests devised? Who comes up with the technology that allows you to drop a little tiny sample of blood into a tube or something like that and figure out whether or not an animal might be infected with, say, heartworms or something? MD: It’s a lot of different people and groups and disciplines. It’s one of the things that I actually enjoy a lot about working at a place like UF where it’s not just veterinarians. The whole campus has experts in a lot of different areas. So, taking a test like a heartworm test, it’s people who can design antibodies to detect that organism. It’s people who can design the fluid handling; it’s people who can convert the test into a little tiny package. MD: So there’s a lot of folks involved to develop a new test. A lot of the mechanics of testing like the heartworm test are fairly well known. So, a lot of tests, if you’re developing a new test, you’re taking currently developed packaging and mechanics, and you’re adapting it to, say, a new disease process. And so a lot of that would be more microbiologists or virologists or individuals who are studying that specific disease, finding something that lets you identify that disease and tell it apart from other diseases that are similar, and then developing that into the technology of an existing test to package that up. DH: And then if this is a test that seems like it can be useful to a pretty large number of veterinarians or other researchers, perhaps it becomes commercially available. Some medical company creates these in volume and sells them to clinics across the country and the world. MD: Yes. And a lot of veterinary schools, including UF, have developed the initial test and then through patent licensing, will license it to companies to then produce the test in volume and sell that out at scale. DH: Yeah. Now, I don’t mean to get too much further down this rabbit hole. But when we think about diagnostic testing for human disease, these tests must be approved, probably by the FDA. Does the same thing hold true for tests for veterinary diseases? MD: Not broadly. The difference is a lot of the requirements are voluntary. So, for instance, UF’s Diagnostic Lab, as well as a lot of other labs across the country, are accredited by a group called the American Association of Veterinary Laboratory Diagnosticians. So that’s a voluntary process. We sought out accreditation. MD: But for that group, if you are performing a test diagnostically on patients, you have to be able to show data that says that the test works the way you say it does, that you understand what the sensitivity and specificity of the test are and that it’s reproducible, and that you’ve – everybody who does the test has been trained in how to run it and interpret it successfully. DH: Yeah. You know, the average pet owner who comes in isn’t going to be aware of the accreditation that you all have sought out and received, but it certainly matters. And if it didn’t, you all wouldn’t have pursued this. Talk about a little bit about why you would seek to voluntarily pursue a certification and what that kind of means to y’ all who do this sort of work. MD: We sought out accreditation for several different reasons. Part of it is our lab and the folks who work in it genuinely have a dedication to quality. We are all pet owners. We all understand what these results mean in terms of the health of the animals that are having the tests done. And so the lab staff has a real dedication to quality. MD: And so this certification is important to them because it serves as a statement of the importance we put on producing quality, reliable results. The other reason for it is it lets us work more cooperatively with the state diagnostic lab and some of the state agencies and participate a little more broadly in animal health in general, because we can show that, yes, not only are we producing quality results because we’re a veterinary institution and a vet school, but that we’ve had external people come through and verify that we are doing what we say we do. And so it was important for a lot of reasons, but those are the main ones. And I will say that our staff really drove accreditation because of the importance that they put on it. They really felt like it was important. MD: It was an important statement for us to make of where we think the quality is and where it needs to. DH: Be when we go backwards and resume discussing, say, a blood sample. I recall a recent visit I had to my doctor’s office when I was asked to give a blood sample. And I’ve done this who knows how many times in my life. I think many of us have. And when the phlebotomist, or whoever it was, did the blood draw, I was reminded of how difficult it can sometimes be for even experienced texts to find a suitable vein and draw that blood. DH: And how I’ve given up allowing them to take the sample from the sort of inside of my elbow, the inside of my arm there in the crook of my arm, and I just point instead to the top of my hand where I have this like bulging vein that goes across and it’s so easy to see. And it occurs to me that drawing blood from an animal might present some challenges, not least of which is a bunch of fur in the way, maybe skin that’s not quite as easy to see through and identify a vein or something at any given point. How challenging is it to sometimes draw blood from, from patients? Especially when you’re talking about so many different kinds of animals. It’s not just dogs and cats, but you can need a blood sample from anything from a bird to a horse. MD: The level of challenge is really going to depend a lot on the animal and the skill level of the person drawing it. I have been lucky through my career to have a lot of very talented technicians who were really good at drawing blood. And the folks at the UF hospitals are excellent technicians. They do an amazing job. I don’t know that I would be very good at it anymore. MD: It’s been a while since I’ve had to draw blood on anything that’s not my own patients. And my wife does a lot more clinical work than I do. So usually, I hold and have her draw the blood nowadays. But yeah, for very small animals it can be really difficult. You have to use small size needles, much like in infants. MD: You’re going to use a much smaller needle than you would for you or I. And so the, a lot of it is experience. So, as you gain experience in species you work with a lot, it becomes easier to get blood samples. And you also learn some tricks in different species to make it a little easier. And so it’s a lot harder in a species you don’t normally work in, because you’re kind of going based on your experience and what the books say, and then you kind of have to try it a little bit. DH: I think many of us are familiar with the smallish sort of vial that is the receptacle for the blood that we give when we need lab work done. But of course, animals being such A wide range of sizes from, you know, like we were saying, a bird that might weigh only a few ounces to dogs that can weigh over 100 pounds, or horses that can weigh many hundreds of pounds, cattle and so forth. How much of a sample do you need of something like blood when you’re trying to diagnose some sort of illness? MD: We can get by with pretty small samples. Usually, we’re talking about a milliliter or two of blood, which is…I mean, if you think about maybe taking a regular sized glass, if you just get liquid on the bottom, you’re probably looking at a milliliter or so. So it doesn’t take very much blood at all. Ideally we get more because it gives us the chance to repeat blood work. MD: If there’s an issue or if somebody decides they want to add another test on, then the more blood that we have, the more opportunities we have to do additional things. But we can get by with very small amounts of blood. And luckily, as technology has advanced, the amount of blood we need keeps decreasing because we’re using a lot of times for a routine chemistry. For instance, you’re looking at chemical reactions to detect various things in blood. MD: The drive has been to use less and less blood over the years. And so the chemistry is still the chemistry. The reactions happen as long as you have enough to react. And so a lot of that can happen with very small volumes of blood. And so when we get exotic species in particular, like birds, especially small birds, small rodents, there’s just no way to get as much blood as you would even out of a cat. MD: And so we have very small blood tubes and can work with fairly small volumes of blood. DH: When you get the blood into a vial or whatever sort of receptacle, what does it take to, I don’t know, keep that from going bad, if I don’t know the proper terminology. But I would think that, you know, blood would tend to want to coagulate or, you know, who knows what else. MD: Yeah, a lot of that depends on what tests you’re running. Sometimes we want the blood to clot because we want the liquid part of the blood and not the cells. And so once the blood clots, we can spin it in a centrifuge to get that liquid off, and then we don’t need the rest of it. Sometimes we want it to have all the cells in the liquid. And for that we use a tube that contains an anticoagulant that stops the blood from clotting. MD: The most common one we usually use is chemical called EDTA. There’s a few others as well. But a lot of your listeners may have heard of heparin. It’s a fairly common drug. And so we have tubes with heparin in them that can stop the blood from clotting as well. DH: Then with something like blood, if you need to divide it up or retest it later, I mean, does it. Does it store. Is it possible to store it? MD: That, again, depends a lot on what test you’re doing. So, for instance, if you are looking for the amount of ammonia in the blood, ammonia goes away very quickly. So it gets drawn into a special tube, it gets put on ice and brought to the lab immediately because we have to test it within somewhere around 30 minutes or else it’s not accurate anymore. For a lot of tests, they’re good for quite a while, especially if processed correctly. So if you’re measuring glucose in the blood, you can measure glucose in the blood after a day, as long as you’ve spun the blood down and gotten the cells out. MD: Because if you leave the cells in, the cells will use up glucose and the glucose will decrease over time. So a lot of that depends on the tests. And I have to say, my specialty is not clinical pathology, who do a lot of the blood testing, but the clinical pathologists are really good about being able to say this test would be good under this condition. And so, generally, we refrigerate the samples that we get to let them be good for longer. And then it comes down to what tests people want to run as to whether that sample is still okay for testing or whether we need a new one. DH: Now, for everyone who is enjoying lunch at this hour, I apologize, but here I want to talk about some types of samples that I don’t know may be more or less challenging to collect. And I’m talking about, say, urine or stool. And it occurs to me that you could probably without a huge amount of difficulty, get many dogs to provide you a urine sample, let’s say. But a cat, I don’t know, that may be a little bit harder to get a voluntary sample. And I couldn’t even begin to tell you about every other kind of animal. DH: How do you go about getting these? MD: There’s a few ways to go around it. For cats, especially, if there’s not multiple cats in a house, there’s plastic litter you can substitute in their litter box so that it doesn’t absorb, so that when they use the litter box, you can then pour the urine out into a cup and collect it that way for all animals, or I guess most animals. There’s also the ability to do what we call a cystocentesis. So you can use a needle and syringe and insert the needle from the outside into the urinary bladder and get urine out that way. Stool samples are usually collected by waiting until the animal defecates and then collecting it. MD: And for most things, that works pretty well, especially for parasites, we try not…
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