"Why don't my numbers match the vet"?

Hello everybody and welcome back to the Canine Corner!

Today's topic;

Why don't my numbers match the vet?

You run a test on your awesome home progesterone system, and you get an 8 ng/ml. "Ok, this seems about right but I would feel better if I checked it with my vet as well". The vet gets a 5ng/ml. How can this be?

Shouldn't they be the same?

This scenario is completely normal, and it's easily explainable as well. Your machine is likely working fine, and so is the vet's machine. How can that be?

In this blog, we will explore why.

P.S

The video below explores why the Mini Vidas and Idexx systems read differently.

Idexx Progesterone Chart

So, why don't they read the same?

I'll jump right into the big reveal, your results don't match the vet because the vet most likely has a different machine. Vets commonly have a Mini Vidas or use an idexx.

But shouldn't all machines read the same?

In a perfect world, yes, but in reality, there is no standard for veterinary machines.

For example, in human lab testing, every machine is calibrated to the same standard and therefore read relatively the same. A 5ng/ml will be a 5ng/ml regardless of where it is tested.

The vet world is different, with less regulation, there is no requirement for machines to read to a certain standard, so they don't.

Don't get me wrong, there still are "standards" in the vet world for progesterone, however, instead of one standard, there are two or three.

The immulite 1000 is considered the "gold standard" of the industry, but even then, only a handful of machines are actually calibrated to match it.

In simple terms, It all depends on what your instrument is calibrated to, or what set of values it uses as reference. For example, the V200 is calibrated to an immulite 1000. So is the idexx, which means in theory the V200 will read similar to the idexx.

However, some machines are calibrated differently, for example, the Finecare is roughly calibrated to the Mini Vidas, and therefore reads very differently than an Idexx will.

For example, estimated ovulation on a Mini Vidas, Finecare and Idexx roughly shake out to the following.

Finecare 6-10 ng/ml

Idexx - 5 ng/ml

Mini Vidas- 9 ng/ml

Assuming the testing process was done correctly, all of these numbers mean the same thing. However, if the right reading chart is not being used, it can be extremely confusing.

Best Practices

Name: Healvet 3000 - Dog Progeterone Machine (Analyzer Only)
Brand: Healvet
SKU: VME-FPKIT-60404
Price: 2599.0 USD
Availability: InStock

1. Find out what machine your vet has.

This step is very important, ask your vet what machine they use. Also, ask for the reading chart that is associated with it. This is pertinent information if you are comparing results with your vet.

2. Compare the meaning of the numbers, not the absolute value.

If you are going to compare results between your machine and your vets, you MUST have both reading charts available. This way you can compare the meaning of the number, the general meaning should match up, often time the absolute value will not. For example a 5 on an idexx and a 9 on a Mini Vidas, are different numbers, but they mean the same thing.

3. Be prepared for some variance.

Simply put, some machines are more accurate than others. Each machine has an acceptable range of results. For example, on the Finecare, we expect a 10% variance, which means that if you test two times using the same blood pull and same exact procedure, your results may differ by up to 10%. For example, a 10 is really between a 9-11.

4. When in doubt, test again.

Human labs do it, and you should too. When a result doesn't make sense or you are a little skeptical, test again. These machines are man-made, and they aren't perfect. A number of things could have gone wrong with the test. Verify you are doing the procedure correctly, and test again. More often than not, this can clear up a lot of confusion.

Understanding the bias between machines is a great start to a successful home testing operation. Always remember to compare the meaning of the numbers and not the absolute value.

'Till next time!

Healvet 3000 Timing Chart.