Introduction to Labwork Part 1

Whether you’ve heard it called “bloodwork” or “Labwork” or “Annual Blood Screening,” it all means the same thing. We’re drawing blood from a pet and submitting it to a laboratory for analysis. I field lots of questions about labwork: what are we looking for, what does it check for, why is it important. I’d like to start a series of posts today that introduce you to the contents and interpretation of labwork in the veterinary field.

Drawing a Sample

Most everyone is familiar with a needle and syringe used to give vaccinations or other injections. This is also the most common way that we draw blood from an animal, as well. There are other ways to draw blood, but we find for veterinary patients that the needle-syringe combination works the best. (On the Human side, they use that odd little needle and sleeve thing, and the blood collection tube gets pushed up into the sleeve to fill with blood. It’s called a vacutainer.)

When we draw blood, we utilize one of a number of different sites where it’s easy to hit a vein. For people, the inside edge of the elbow is often used. In pets, depending on species, we aim for a vein that’s close enough to the surface for us to feel it. All of the fur on pets can make it very difficult to -see- the vein, so much of what we do is by touch.

The sites we prefer are: jugular vein (dogs and cats), inside of the thigh (cats), outside of the hock joint (dogs), and the vein on the lower front leg (dogs and cats). My preferred place overall is the jugular vein. It allows us to draw the required amount of blood very quickly, which means the patients don’t have to hold still for very long. This vein is also generally quite close to the surface, which means it’s easier to get the needle in the right spot. Most animals tolerate the small pick from the needle very very well. However, for patients that are too frightened to hold still this way or object to the small pick of the needle, we select a different spot.

Once the sample is drawn, we put the blood into one or more special test tubes. These tubes may contain a chemical to prevent the blood from clotting, or a special gel that helps the blood clot and then separates the various parts of the blood when the tube is spun in a centrifuge. The type of tubes that we use are determined by what which tests we need to run. The tubes have simple ‘common’ names that we use simply because they’re easy to remember. “Purple Top,” “Tiger Top,” “Serum Sep,” “Blue Top.” The colors refer to the color of the rubber stopper in the tube. Here’s a look at a couple of the tubes we use most commonly.

Sample Processing

All of our blood is sent to an outside lab. This lab is a veterinary-only company that processes hundreds of different types of tests. They’re able to run blood tests, bacterial cultures, urine samples, histopathology, and more. We use a special web site to log each pet into the lab system so that each patient has a unique barcode for their sample. The barcode tells the lab which tests to run for that patient’s sample. A printed form is also generated as a backup for the barcode. Samples are packaged individually in special ziplock bags with the identifying paperwork. Each tube is labeled with the patient’s name. Samples are kept at the hospital in the refrigerator until we’re finished for the day. Then, a courier comes to pick up the blood. The blood may go by car or plane to the outside lab. I believe that the closest lab to us with the company we use is Elmhurst, IL.

The lab runs the tests overnight. Most types of blood tests have results completed that night. We get the results faxed to us by about 11am the following morning. Sometimes it’s a bit earlier, sometimes it’s later. The really great part, though, is that we almost always have results within 24 hours. Certain tests take longer than that, but the routine stuff is back the next day like clockwork. This allows us to call you the following day with results. I’m very proud of the fact that we’re able to provide such quick service in our profession. I’ve waited anywhere from a week to a month to get results from my own doctor!


Once the results are back, they’re placed in the patient’s file and returned to the doctor for interpretation. We read over the results and investigate anything that’s out of the normal range of results. In some cases, the bloodwork is providing confirmation of a diagnosis that was made during the examination the day before. In some cases, we’re able to detect a problem that wasn’t found on the physical exam. Most importantly for healthy pets, we’re able to detect trends. For example, if an otherwise healthy dog is having a steady increase in kidney values over a 3 or 4 year period, we know that kidney health is declining for that patient. We’re able to start treatment much sooner, which leads to a better quality of life over a longer period of time. We really rely on bloodwork to help us find out the things that our patients can’t tell us because they don’t speak.

The vets (sometimes techs) call clients directly to discuss the results of any tests that were sent out. This is something that I’m also very proud of. We feel it’s important to be able to speak directly with a client, especially when results are abnormal. We’re able to explain the information gained, discuss treatment options, and schedule any necessary follow-up visits. I hope that clients feel that this is something special that sets us apart from our human medical counterparts. We’re certainly trying to provide individual, focused attention to each patient and client. We’re also happy to call to deliver good news! Normal bloodwork is a -good- thing!

Next week, I’ll start talking about the different tests and what they all mean. I hope everyone enjoy the holiday weekend!

Fireworks2010 53
I took this photo in Bay City last year for the fireworks festival. I didn’t make it up this year, unfortunately. If you ever have a chance to go to Bay City for the 4th, it’s well worth it. Easily one of the best fireworks shows I’ve seen anywhere.


1 Comment

Filed under laboratory

One response to “Introduction to Labwork Part 1

  1. Once again, I learned something new 🙂 And I heartily agree about getting test results back waaaay quicker from you than from my own doctor! Happy 4th of July ~ the Bay City fireworks are great!

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