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Free Androgen Index Testing (FAI)

All you need to know about testing Free Androgen Index levels with a laboratory test

  • What is the Free Androgen Index test for?
  • How to test Free Androgen Index?
  • What if Free Androgen Index results are high?
  • What if Free Androgen Index results are low?
  • Who should take the Free Testosterone & SHBG Blood test?
  • Do I need to prepare in any specific way for the FAI test?
  • Is the Free Androgen Index test suitable for everyone?
  • Are there any risks associated with the FAI test?
  • What if the FAI test results are negative?
  • What should I do if my FAI test results are positive?
  • How do I interpret FAI test results?
  • How does the Free Androgen Index test work?
  • What symptoms can the FAI test help diagnose?
  • What is the Free Androgen Index (FAI) test?

Free Androgen Index Testing UK Statistics 2026

Icon For Free Androgen Index
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23.1% of people tested have Free Androgen Index levels which are too high.

And 11.5% have levels that are too low.

71.5

Low
< 35.000

Normal
35.000 - 92.600

High
92.600 +

The average Free Androgen Index result is 71.5 %
Note what is normal for you may differ for your age and sex.

Are you in the 65.4% with normal results?
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What Is The Free Androgen Index Test For?

A FAI (Free Androgen Index) test evaluates the ratio of total testosterone to sex hormone-binding globulin (SHBG) in the blood. It helps estimate the amount of free, or unbound, testosterone which is biologically active and available for the body to use.

This test is often used to assess hormonal balance, particularly in diagnosing conditions related to abnormal testosterone levels.

How To Test Free Androgen Index

By buying a laboratory test kit with professional nurse or clinic collection, you can accurately measure Free Androgen Index for total reassurance.

Professional analysis in an accredited laboratory ensures rapid result delivery.

The Vitall Free Testosterone & SHBG nurse or clinic test kit includes a Free Androgen Index test and is available for just £79.00.

Tests which include a Free Androgen Index test:

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Take Control Of Your Health | Home Blood Testing Services

Free Testosterone & SHBG Test Kit

Free Testosterone & SHBG test kit
Free Testosterone & SHBG Home Test Kit UK

Free Testosterone & SHBG Test Kit

Assess your Free Androgen Index (FAI) for optimum control

£79.00

View Full Details ›

What if Free Androgen Index Results Are High?

High Free Androgen Index (FAI) means there is a higher ratio of free testosterone relative to sex hormone-binding globulin (SHBG) in the blood, suggesting increased bioavailable testosterone.

High FAI can be associated with a range of symptoms and conditions. In men, it may be linked to acne, increased body hair, aggressive behavior, and an increased risk of prostate problems. In women, high FAI is often seen in conditions such as polycystic ovary syndrome (PCOS), and may be linked to irregular menstrual cycles, excess facial and body hair, and acne.

Causes of a high FAI can vary and may include hormonal imbalances, use of certain medications, or underlying health conditions. This result is commonly reviewed further to clarify the underlying cause and guide treatment options, which may include lifestyle changes, medication to balance hormone levels, or addressing underlying health issues.

Test results are commonly shared with the GP or the medical practitioner who requested the test.

What if Free Androgen Index Results Are Low?

Low Free Androgen Index (FAI) suggests a lower than normal amount of available free testosterone relative to sex hormone-binding globulin (SHBG). This pattern can indicate reduced bioavailable testosterone.

Low FAI is often associated with symptoms such as decreased libido, fatigue, muscle weakness, and in some cases fertility issues. Possible underlying causes vary and can include hypogonadism, liver disease, or thyroid disorders.

This finding is commonly reviewed further to clarify the underlying cause and to consider potential treatment options. Options sometimes discussed include lifestyle changes, addressing underlying health conditions, or hormone replacement therapy, depending on the cause and overall health context.

The test results are typically shared with the GP or the medical practitioner who requested the test.

Who Should Take This Test?

Measure your Free Androgen Index levels and assess your free androgen index (fai) for optimum control with a Free Testosterone & SHBG nurse or clinic finger-prick bloodtest kit

You get the convenient testing with the reassurance of professional clinical analysis. Your results are delivered quickly & securely online.

This Free Testosterone & SHBG Test is advised if you:

  • want the convenience of home testing without waiting for a GP appointment;
  • need a high quality, clinically accredited test done in a professional clinical laboratory.

Do I need to prepare in any specific way for the FAI test?

No specific preparations are required for the FAI test. However, to get the most accurate results, it's recommended that the finger-prick blood sample be taken in the morning when hormone levels are at their peak.

Is the Free Androgen Index test suitable for everyone?

The test is suitable for most adults who may be experiencing symptoms of hormonal imbalances, although it is particularly relevant to women with symptoms of PCOS and men with symptoms of hypogonadism. However, if you believe you may benefit from such a test, consider discussing this with your healthcare provider.

Are there any risks associated with the FAI test?

The FAI test is minimally invasive, with the main risk being slight discomfort or minor bruising at the site of the finger prick. It's also possible to have a false negative or positive result, which means it's important to discuss the test and your results with your healthcare provider.

What if the FAI test results are negative?

If your test results are within the normal range, this generally suggests that your body's testosterone and SHBG levels are balanced. However, if you're experiencing symptoms that prompted you to take the test, you should still discuss these with your healthcare provider.

What should I do if my FAI test results are positive?

Abnormal results may indicate a hormonal imbalance, but it's important to take these results to your healthcare provider for a complete evaluation and to discuss next steps, which may include further diagnostic tests or treatments.

How do I interpret FAI test results?

Your FAI test results will be given as a ratio value. In a normal range, the value for women should be 0.5-3.0 and for men, 0.8-1.0. Your results will always contain the latest range for your age and sex.

Higher than normal results may indicate conditions like PCOS in women, whereas lower than normal results may be indicative of testosterone deficiency in men. However, interpretation should ideally be performed by your healthcare provider or a medical professional, since these values can vary based on individual health and environmental factors.

How does the Free Androgen Index test work?

The FAI test works by analysing a sample of blood, collected via a finger-prick, for levels of testosterone and SHBG. The sample is then posted to a UKAS accredited laboratory for analysis, and the results are interpreted to provide an FAI value.

What symptoms can the FAI test help diagnose?

Symptoms of conditions that can be diagnosed using the FAI test can include irregular or absent menstrual periods, abnormal body and facial hair growth in women, fertility problems, fatigue, loss of muscle mass and sexual problems in men. If you're experiencing these symptoms, you might want to consider taking an FAI test.

What is the Free Androgen Index (FAI) test?

The Free Androgen Index (FAI) test is a diagnostic tool used to measure the ratio of testosterone, which is a type of androgen, to a protein known as sex hormone binding globulin (SHBG). The test is used to evaluate and diagnose hormonal imbalances that may be indicative of conditions such as PCOS in women, or hypogonadism and androgen deficiency in men.

Other Biomarkers Often Tested With Free Androgen Index

Urine, swab or bood test. This test is available to buy online Free Androgen Index
Urine, swab or bood test. This test is available to buy online Free Testosterone
Urine, swab or bood test. This test is available to buy online Sex Hormone Binding Globulin

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