Confused by American Standard Unit for Free Test

529 pmol/L * 1 nmol / 1000 pmol * 288.431 ng / nmol * 1 L / 10 dL = 15.3 ng/dL = 153 pg/mL to 3 sig figs as per measurement

Note: 1 ng/dL = 10 pg/mL

What you typically see is ng/dl if you are getting an accurate equilibrium dialysis free T test. Ref ranges vary from 5 up to 28 ng/dl depending on lab. Your number above is 15.3 ng/dl for comparison.

Also there’s a misleading direct RIA fT test that is typically reported in pg/ml.

You’d have to post an old test or do some more hw to determine what you typically get back from lab.

Who is they?

Your TT above is 597 ng/dl. You can use online calculator to plug in SHBG and TT and confirm fT number i converted for you.

http://www.issam.ch/freetesto.htm

Another slightly rounded set of conversion factors here:

https://www.questdiagnostics.com/dms/Documents/test-center/si_units.pdf

Reinforces a point about roundoff error on intermediate calculations i made in another post.

2 Likes