Free Androgen Index
The Free Androgen Index (FAI) Test is used to estimate the amount of active (free) testosterone in the blood relative to sex hormone-binding globulin (SHBG). It helps assess androgen status, particularly in cases of polycystic ovary syndrome (PCOS), hirsutism (excess hair growth), irregular menstrual cycles, infertility, or low testosterone symptoms in men. This test is valuable in determining whether testosterone levels are appropriately balanced, helping to diagnose conditions related to hormonal imbalances, reproductive health, and metabolic disorders.
Test details
Sample type
Blood
Time of day
No Specific Time Needed
Fasting required
Yes
Results timeframe
Within 7 days
Preparation
Fast for 8-10 hours before the test; avoid food and beverages other than water; continue taking prescribed medications.
What's measured in this test
Testosterone And SHBG
Checks testosterone and its availability.
Common reasons for testing
- Polycystic Ovary Syndrome (PCOS) – Helps assess androgen levels in women with PCOS symptoms such as irregular periods, acne, and excessive hair growth.
- Hirsutism or Hair Loss – Identifies elevated androgen levels in women experiencing excessive hair growth or hair thinning.
- Testosterone Deficiency in Men – Assesses low testosterone levels that may contribute to fatigue, low libido, or reduced muscle mass.
- Infertility Investigations – Helps evaluate hormone-related causes of fertility issues in both men and women.
- Metabolic Disorders – Supports the diagnosis of conditions affecting hormonal balance, such as insulin resistance.