Functional Lab Testing

The term “functional labs” has become a bit of a buzz word in the field of medicine over the last 10 years. It could be said that all blood tests are functional tests since they help the doctor get a better idea of how certain systems or organs are working.

However, functional blood tests take it to another level giving the doctor a better understanding of not just what is wrong, but also why it’s wrong. Functional blood tests often look at multiple systems simultaneously because a problem in one system will often throw things off in another system. 

Here’s an example: 

Let’s take a look at the traditional tests ordered when a thyroid problem is suspected. 

• • TSH
  • T4

A traditional approach only looks at two factors, TSH and T4. If there is an obvious problem with the thyroid it will usually show up on those tests. They are sensitive to thyroid problems, but not helpful in determining the underlying cause. So the patient gets a prescription drug to artificially and temporarily manage the symptoms all the while ignoring the root cause.  

Now let’s take a look at the functional tests ordered for suspected thyroid problems:

• • TSH
  • T4
  • T3
  • FT4
  • FT3
  • T3 Uptake
  • Reverse T3
  • TPOAb
  • TgAb

As you can clearly see, the functional approach includes several tests that will not only show the obvious problem, but will also shine a light on why the obvious problem exists. With the doctor’s help the patient can work on the root cause(s) and stand a much higher chance at getting back to normal instead of taking medication for the rest of their life.