Quest vs. Labcorp Free Test Ranges

[GreenMachineX]

I was using an online calculator to see what my free T is from Quest to Labcorp, where on quest my free T is top of range in pg/mL, and Labcorp was ng/dL (I think?). Anyway, converting my top of range free T to Labcorp free T in their Unit resulted in having a free T in the middle of Labcorp's range. So they define normal differently? Or is that not an accurate way to equivalent units?

 

[Cataceous]

Though it may change eventually, at this time virtually no free testosterone test can be directly compared to any other that uses a different method or lab, or to the calculated values. Furthermore, direct immunoassay-based tests are very inaccurate and should not be used at all. You can request a test that uses an accurate method, such as one based on equilibrium dialysis or ultrafiltration. You would then note where your result lies in the reference range. Alternatively, if your numbers aren't extreme then you may get a reasonable estimate from a calculator. However, the calculators also have different reference ranges. A healthy normal—as opposed to only normal—reference range for a Vermeulen free testosterone calculator is about 10-20 ng/dL. The healthy normal range for the Tru-T calculator is 16-31 ng/dL.

 

[GreenMachineX]

Though it may change eventually, at this time virtually no free testosterone test can be directly compared to any other that uses a different method or lab, or to the calculated values. Furthermore, direct immunoassay-based tests are very inaccurate and should not be used at all. You can request a test that uses an accurate method, such as one based on equilibrium dialysis or ultrafiltration. You would then note where your result lies in the reference range. Alternatively, if your numbers aren't extreme then you may get a reasonable estimate from a calculator. However, the calculators also have different reference ranges. A healthy normal—as opposed to only normal—reference range for a Vermeulen free testosterone calculator is about 10-20 ng/dL. The healthy normal range for the Tru-T calculator is 16-31 ng/dL.

Gotcha, thanks.