Lab Comparison - Total T

[S1W]

I recently noticed while looking back at some pre-TRT labs that the Free T results and reference ranges between Quest and LabCorp differed significantly. With the help of this forum, I learned that those values can't be compared.

Can the same be said for Total T readings? For example, I have these two different pre-TRT results:

LabCorp: Total T 378 (range 248-1197)
Quest: Total T 333 (range 250-1100)

 

[CoastWatcher]

I would never try and compare total or free testosterone reading from lab to lab. Settle on one lab and have all blood drawn there while controlling for as many variables (time of day, fasting/not fasting) as you possibly can.

That said, 333/378 may well be a normal fluctuation in serum levels.