How can total and free testosterone levels be normal, but free and weakly bound percentages be off? (33yr old female). total is 10ng/dl, f&w bound is 4.8ng/dl and f&w bound % is 48.4% (high normal stated to be 18%). thank you for your help?

Free testosterone binds to sex hormone binding globulin and serum albumin. The albumin-bound testosterone connection is weak and it is included in free and weak portion. For you, the percentage of free and weakly bound testosterone is high. So your total testosterone is low but the free portion (Free and Weak) is normal because you have high percentage F&W. In summary, you are not deficient in T.

This depends a bit on which assays they are using. Biotin can interfere with some of them. If taking tell your team and think about stopping and repeat. R u taking any hormones at all esp Birth control meds