Testosterone

Background

Testosterone is the major androgenic steroid hormone. In men, testosterone is mainly synthesised in the Leydig cells of the testes, and is regulated by LH secreted by the anterior pituitary. A negative feedback control mechanism exists with the hypothalamus and pituitary. Testosterone is responsible for the development of secondary sexual characteristics in men, and serves to maintain the function of the prostate and seminal vesicles. Most of the circulating Testosterone is bound to the carrier protein SHBG.

In women, small quantities of testosterone are synthesised in the ovaries. In physiological concentrations, androgens have no specific effect on women. Increased levels of Testosterone, however, can lead to virilisation.

The determination of Testosterone in women is helpful in the diagnosis of polycystic ovaries, ovarian tumours, adrenal tumours and adrenal hyperplasia. Testosterone measurements in men are useful when low levels of the hormone are suspected. Common causes of decreased levels in males include:- Hypogonadism, oestrogen therapy, Kleinfelters syndrome, hypopituitarism and hepatic cirrhosis.

Reference ranges

Male: 10 – 30 nmol/L
Female: 0.7 – 2.8 nmol/L

Specimen requirements

Sample type:

• Serum

Sample identification:

• Three patient identifiers from
  • Name
  • D.O.B.
  • Address
  • N.H.S. number
  • Unit Number
  should match on the specimen and request form. This check may be performed prior to centrifugation by the Central Sort department.

Turnaround time

6 hours