Repeating Laboratory Tests – It’s Not (Always) About the Money

Published Apr. 9, 2012

I had a phone conversation with a client over the weekend that did not go as well as I would have liked. Granted, the gentleman was very upset because we were ultimately trying to determine whether or not it was time to euthanize his beloved dog, but I just never felt like I got through to him about the benefit of repeating a lab test before making the decision.

The dog in question had been previously diagnosed with hemangiosarcoma of the spleen. He did well after his surgery and chemotherapy, but over the last 24 hours had become more withdrawn, wasn’t eating, and was shaking. I told the owner that my top two rule-outs were that he was in pain or that he was bleeding internally. To determine the most likely cause, a veterinarian would need to perform a physical exam and most likely run a packed cell volume (PCV). Figuring out whether pain or blood loss was the biggest contributing factor was crucial in this case because we could treat the former (the dog wasn’t currently on any pain relievers) but not the latter.

In response to my recommendation, the dog’s owner responded, "But he just had a PCV done last Thursday." To which I replied, "Great, then we’ll have something recent to compare today’s result to."

Confusion ensued. Despite multiple attempts to explain that if his dog was bleeding internally his PCV today could be much lower than it was three days previously, the owner never seemed to “get” the value of repeating this extremely quick and inexpensive test. He ended the conversation by saying he was going to get his "regular" vet (I was called in to consult on end of life care) to take a look at his dog. I sure hope he did.

This conversation got me to thinking about how frequently I hear owners say something like, "But Fluffy just had blood work, a urinalysis, a heartworm test, a fecal exam, etc. Why do we need to run another one?" Hopefully, I’ve been more successful than I was over this weekend in explaining the value of repeat testing under certain circumstances. My reasoning generally falls into one of two categories:

Things can change, and change fast, when a pet is sick. For example, blood chemistry values, cell counts and blood gas levels can rise and fall over just a matter of hours. It can be dangerous to rely on "old data" when a patient’s condition is in flux.

Tests are not 100 percent accurate. Sometimes a result just seems out of whack with a patient’s general condition, and a doctor should confirm the anomalous finding before acting on it.

Now I’m not saying that clients should blindly accept a veterinarian’s recommendation for repeat testing. You have every right to ask the doctor to explain why you should spend your money in this way. Just understand that there are often very good reasons to do so that have absolutely nothing to do with padding the bill.