Free testosterone – FTST

Testosterone is an organic chemical compound that functions as the main sex hormone in men. It is produced primarily in the testes, but small amounts are also produced by the adrenal glands (in both men and women), and in women additionally by the placenta and ovaries. 

Free vs. Total Testosterone – Differences 

In the blood, testosterone exists in three forms: free (1–4%), bound to albumin (below 44%), and bound to SHBG protein (around 55%). Bioavailable testosterone is considered to be the free form and the form bound to albumin. 

The total testosterone test measures the combined hormone level (free and bound), which is sufficient in many cases. However, when SHBG levels are abnormal, the free testosterone test is more reliable. 

Indications for Testosterone Testing 

Testing testosterone levels – both free and total – is recommended in the following cases: 

• diagnosing gonadal hormonal dysfunction; 
• suspected Klinefelter syndrome, polycystic ovary syndrome (PCOS), adrenal disorders; 
• in women: excessive hair growth (hirsutism), irregular cycles, difficulty getting pregnant; 
• in men: decreased libido, erectile dysfunction, infertility. 

Low and High Free Testosterone Levels 

Low free testosterone levels may indicate: 

• underdevelopment of the gonads, 
• viral infections (e.g. mumps), 
• testicular damage, 
• hyperprolactinemia, 
• malnutrition, 
• changes in transport protein levels. 

Excessively high free testosterone levels occur in, among others: 

• adrenal hyperplasia, 
• tumors of the adrenal glands or testes, 
• polycystic ovary syndrome (PCOS), 
• hyperthyroidism, 
• Cushing's syndrome. 

How to Test Testosterone – Preparation 

• A testosterone test is performed using a blood sample.
• Fasting is not required.
• It is important to visit the laboratory between 7:00 AM and 10:00 AM due to the hormone's daily secretion cycle.
• In women, the best time to test testosterone is on days 2–5 of the menstrual cycle (unless advised otherwise by a doctor).
• You should inform your doctor about all medications being taken that may affect the result, such as androgens, estrogens, anticonvulsants, or steroids.

Testosterone Test Results 

• Test results are available within 8 business days. 
• They can be collected in person or accessed online (available upon prior registration at the reception). 
• If the results are abnormal, it is advisable to consult a doctor to discuss further diagnostic steps. 

1. How to test testosterone? 
Testosterone is tested using a blood sample. You just need to go to a testing center in the morning (between 7:00 AM and 10:00 AM). 

2. How much does a testosterone test cost? 
The cost of a testosterone test depends on the laboratory. The price starts at 89 PLN. 

3. What is the difference between free testosterone and total testosterone? 
Total testosterone is the sum of free testosterone and testosterone bound to proteins. Free testosterone is the biologically active form, important when SHBG is abnormal. 

4. What are the normal levels of free testosterone (pg/ml)? 
The normal levels of free testosterone depend on age, sex, and the testing method. It is important to compare the results with the reference values provided on the test result. 

5. Can the testosterone test be done online? 
Yes, you can register for a testosterone test online and receive the results over the internet. You will receive login details to access the system at the reception. 

6. When is the best time to take the testosterone test? 
The best time to test testosterone is in the morning hours. Women should test between the 2nd and 5th day of their menstrual cycle. 

7. How should I prepare for the testosterone test? 
You do not need to fast. Avoid intense physical exercise the day before and inform about any medications that may affect the result.