Biomarker Reference · FAI
Free Androgen Index (Dried Blood Spot, Calculated) (FAI) is a clinical biomarker used in male-hormones assessment. The free androgen index is a calculated ratio of total testosterone (in nmol/L) to SHBG (in nmol/L), multiplied by 100, that estimates bioavailable androgen activity when direct free-testosterone assays are not performed. It is measured in 1 laboratory test on BiomarkersLabs.com.
The free androgen index is a calculated ratio of total testosterone (in nmol/L) to SHBG (in nmol/L), multiplied by 100, that estimates bioavailable androgen activity when direct free-testosterone assays are not performed. It correlates with free testosterone but is not a direct measure and may be misleading when SHBG is at physiological extremes.
FAI is used primarily to assess hyperandrogenism in women and to gauge androgen bioavailability in men with borderline total testosterone. It is more informative than total testosterone alone when SHBG is abnormal, though direct measurement of free testosterone by equilibrium dialysis or tracer methods is the reference standard.
Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.
1 test on BiomarkersLabs.com include this biomarker.
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