What is the reference range for Free Androgen Index?

The standard reference range for Free Androgen Index is Male <100; female <5; calculated as (total testosterone ÷ SHBG) × 100.. Reference ranges vary by laboratory and assay platform — interpret in context of the issuing laboratory's stated range.

Which tests measure Free Androgen Index?

Free Androgen Index is measured in 1 test on BiomarkersLabs.com, including Blood Spot LCMS Hormones 7 with SHBG and Thyroids.

Biomarker Reference · FAI

What does the Free Androgen Index test measure?

Q: Which tests measure Free Androgen Index?

Free Androgen Index is measured in 1 test on BiomarkersLabs.com, including Blood Spot LCMS Hormones 7 with SHBG and Thyroids.

Free Androgen Index (FAI) is a clinical biomarker used in thyroid-endocrine assessment. The free androgen index is a calculated ratio that estimates bioavailable testosterone by dividing total testosterone by SHBG. It is measured in 1 laboratory test on BiomarkersLabs.com.

Reference Range: Male <100; female <5; calculated as (total testosterone ÷ SHBG) × 100.
Units: ratio
Measured In: 1 test
Category: Thyroid

Functional medicine optimalOptimal FAI thresholds are not rigorously defined for dried blood spot platforms; conventional serum-based cut-offs (FAI >5 in women suggesting hyperandrogenism) are applied with caution and method-specific validation.

What is Free Androgen Index?

The free androgen index is a calculated ratio that estimates bioavailable testosterone by dividing total testosterone by SHBG. It correlates reasonably well with free testosterone measured by equilibrium dialysis and is more accessible than direct free hormone assays.

Why is Free Androgen Index measured?

FAI is used to identify hyperandrogenism in women with polycystic ovary syndrome and to assess functional androgen status in men when SHBG is abnormal. It helps practitioners decide whether a borderline total testosterone is clinically significant or merely reflects altered binding-protein concentrations.

Reference ranges

Standard reference: Male <100; female <5; calculated as (total testosterone ÷ SHBG) × 100.
Functional medicine optimal: Optimal FAI thresholds are not rigorously defined for dried blood spot platforms; conventional serum-based cut-offs (FAI >5 in women suggesting hyperandrogenism) are applied with caution and method-specific validation.
Units: ratio

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.

Tests that measure Free Androgen Index

1 test on BiomarkersLabs.com include this biomarker.

BML-THY-030Comprehensive

Blood Spot LCMS Hormones 7 with SHBG and Thyroids

Free Androgen Index reference range in this test: Male <100; female <5; calculated as (total testosterone ÷ SHBG) × 100.

Related clinical conditions

Related Biomarkers

Frequently measured alongside

Oestradiol (Dried Blood Spot)E22 tests ProgesteroneP41 test TestosteroneT1 test Dehydroepiandrosterone Sulphate (Dried Blood Spot)DHEA-S2 tests CortisolF1 test Thyroid-Stimulating HormoneTSH5 tests Free ThyroxineFT45 tests Free TriiodothyronineFT35 tests

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