Androgen Index
Calculated ratio assessing bioactive androgen levels by comparing total testosterone to sex hormone-binding globulin.
Full Definition
The androgen index, also known as the free androgen index (FAI), is calculated by dividing total testosterone by sex hormone-binding globulin and multiplying by 100. This calculation provides an estimate of bioavailable androgens without requiring direct free testosterone measurement. The index is particularly useful in evaluating hyperandrogenism in women and monitoring androgen status when SHBG levels are altered by factors such as obesity, insulin resistance, or hormonal contraceptives. Clinical editors should note that while this calculation is widely used, it may not accurately reflect free hormone levels in all clinical situations.
Usage
Usage note: Specify calculation method when documenting androgen index results.
In Context
- "The patient's elevated androgen index suggested biochemical hyperandrogenism despite normal total testosterone." — PCOS evaluation report
- "Androgen index calculations should account for laboratory-specific SHBG reference ranges." — Laboratory calculation protocol