Lab results variation on Testosterone

[ron_bucher]

I had two MD appointments, and each MD ordered a Testosterone check. I took both orders to my usual lab to get a single blood draw for both lab orders. The standard T test done by the onsite lab showed T = 262. The "advanced" T test (which also include Free T) was done by an offsite lab and showed T = 380. Anyone ever see a 45% variance between labs doing the same test on the same tissue specimen?

[treedown]

I know my first PSA test was a different assay then my second and the second said it would be as much as 20% different than others. Any notes on your test result? Sorry no idea if T is the same.

[Shanti1]

I have seen a pretty large variation in hormones drawn at the same time but that seems exceptionally large. Check that they are the same methodology as labs offer T measured by both ECLIA and Tandem MS. Are the reference ranges on each the same?

[Hidden]

Ron, I have had over 120 T tests in 16 1/2 years. I always have with a PSA tests. First T lowers during day. The morning test will always be higher than the afternoon test. In my testing I am tested for Total T and hsT. Total T is always higher than hsT.

Think of it this way: pretty much all test for Total T; some want to also test for serum testosterone. Most do not think this is important; however a researcher will also want to know how much testosterone in bound with say albumin. The reason is that when the bound testosterone hit the capillary system, the albumin dissipates leaving plain old testosterone.

My researcher always discussed Total T with me..... the other was for his research which needs a definitive score of both.

In everyone of my testosterone tests, Total was always higher the Serum.

Look at the two different lab reports and see exactly which lab reported which test.

GD

[NecessarilySo]

The results of one of my T blood tests was over 50% difference.

Note that a pg.dl is 1/1000 a ng/dl, and Free T is measured in pg/dl while T is measured in ng/dl

[j-o-h-n]

Both lab personnel need eye exams.....

Good Luck, Good Health and Good Humor.

j-o-h-n Saturday 11/14/2020 7:40 PM EST

[NewAgeBrother]

My experience has been that an inhouse lab tend to be less accurate that dedicated outside labs e.g., LabCorp. I know this has been the case personally for measuring PSA -- the inhouse lab was consistently lower even though the assay method was the same as the outside lab.

How did I know the inhouse lab was off? I used another outside lab, this time Quest - same assay, and it was more inline with LabCorp. I told my doctor this and he was going to speak with the person who ran the inhouse lab but I never heard the outcome.

So, this is similar to the clock problem. You have two clocks but they show different times. Which one is right? Introduce a third clock into the mix and average the two that are nearest each other. This is why the Apollo missions to the moon had three computers working always on the same equations.

[ron_bucher]

My oncologist was stumped, but my urologist figured it out. The two labs have different reference ranges for the overall T test. The confusion started because my hospital lab patient portal shows both tests under the same reference level, which is misleading at best. The bottom line is pay attention to the reference level, which may vary from one lab to another!