Free testosterone – FTST

Free Testosterone (FTST)

Testosterone in the blood is found in its free form (1-4%), bound to with albumin (less than 44%) and bound to the protein SHBG transport protein (about 55%). As bioavailable (BAT), it is considered to be testosterone free and bound to albumin.

The determination of total testosterone concentration reflects the amount of of bound and free hormone, but does not allow assessment of the content of the individual fractions. In many cases, it is sufficient for assessing testosterone synthesis. However, in cases where the concentration of SHBG is abnormal, total testosterone levels do not accurately reflect the amount of bioavailable testosterone. In such situations situations, a better test is to determine the concentration of testosterone free.

Indications for the test

The indications for testing testosterone levels free are as follows:

• assessment of gonadal hormonal function;
• helpful in the diagnosis of adrenal disease, Klinefelter syndrome, polycystic ovary syndrome;
• in women in cases of suspected hirsutism (excessive male-type body hair), menstrual disorders, problems with getting pregnant;
• in men, decrease in libido, erectile dysfunction, fertility;

Reduced free testosterone levels

Reduced levels of free testosterone occur in cases of underdevelopment of the gonads, defects occurring during the synthesis of testosterone, viral infections of the gonads (including testicular inflammation caused by mumps), testicular damage due to mechanical trauma or alcohol abuse, hyperprolactinemia, malnutrition of the patient, and changes in concentrations of transporter proteins.

Increased free testosterone levels

An elevated level of free testosterone can occur as a result of congenital or acquired adrenal hyperplasia, tumors of the testes or adrenal glands, polycystic ovarian syndrome, hyperthyroidism, the presence of ovarian tumors that secrete androgens, the syndrome of Cushing's syndrome, and abnormal concentrations of proteins that bind and transport sex hormones.

Test results

• Test results are available within 8 working days.
• It is possible to collect them at the reception desk of the previously chosen Centre.
• The results can be accessed online. To do this, you have to visit the reception desk to generate a password in the Centre of your choice.