Serum total testosterone measurement is used in the following cases:
- Assessment of men with symptoms or signs of possible hypogonadism, such as loss of libido, erectile dysfunction, gynecomastia, osteoporosis, or infertility
- Assessment of boys with late or early adolescence
- Monitoring of testosterone replacement therapy
- Monitoring of anti-androgen therapy (e.g. prostate cancer, early adolescence, treatment of idiopathic hirsutism, etc.)
- Assessment of women with hirsutism, masculinization, and oligomenorrhea
- Assessment of women with symptoms and signs of testosterone deficiency
- Assessment of infants with ambiguous genitalia
- Diagnosis of androgen-secreting tumors
More information
Testosterone is the primary male hormone. It is responsible for the development of external genitalia and secondary sexual characteristics in males. In women, its main role is as a precursor to estrogen. In both sexes, it exerts anabolic effects and affects behavior.
In men, testosterone is the main androgen and is secreted by the interstitial cells of the testes, known as Leydig cells. Testosterone promotes the growth and development of the genitals in males, contributes to muscle growth, stimulates hair growth in the armpits, face, and pubic area, and promotes spermatogenesis. Testosterone is usually measured in tests for the detection of impotence and in the investigation of infertility.
In women, testosterone is secreted in small amounts by the ovaries and adrenals. The maximum levels are noted in the middle of the menstrual cycle. Testosterone measurement is commonly used for the evaluation of ovarian tumors, hirsutism, and in the investigation of infertility.
The measurement of blood testosterone levels, in combination with the measurement of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels, helps assess the potential dysfunction of the gonads (testes and ovaries) in both sexes. Testosterone circulates in the blood both as free and as bound in plasma proteins (sex hormone-binding globulin, SHBG). Total testosterone is a measure of total circulating testosterone (free and bound). Free or unbound testosterone is the active form of testosterone.
Possible Interpretations of Pathological Values
- Increase (Men): Adrenal tumors, androgen-secreting tumors, celiac disease, Cushing's syndrome, hyperthyroidism, early puberty, Reifenstein's syndrome. Medications that can increase testosterone levels in men: bicalutamide, cimetidine, finasteride, leuprolide, nilutamide, phenytoin, pravastatin, rifampicin, tamoxifen, sodium valproate
- Decrease (Men): AIDS, bilateral cryptorchidism, chronic renal failure, cirrhosis, congenital adrenal hyperplasia, Down syndrome, Klinefelter syndrome, myotonic dystrophy, primary hypogonadism, secondary hypogonadism. Medications that can lower testosterone levels in men: carbamazepine, cimetidine, corticosteroids, cyclophosphamide, digoxin, estrogen, finasteride, gemfibrozil, goserelin, ketoconazole, leuprolide, narcotics, pravastatin, spironolactone, tetracycline, verapamil
- Increase (Women): Adrenal tumors, Cushing's syndrome, molar pregnancy, obesity, polycystic ovary syndrome, androgen-containing supplements, ovarian tumors. Medications that may increase testosterone levels in women: antiepileptic, bromocriptine, clomiphene, danazol, estrogens, minoxidil, pravastatin, rifampicin, tamoxifen
- Decrease (Women): -
Important Note
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.
