Testosterone, total

What it measures

Testosterone is the main androgen produced by the testes and, in smaller amounts, the ovaries and adrenals. It is measured for male hypogonadism, and for hirsutism, acne and PCOS in women.

Specimen and preparation

• Specimen: Serum or lithium-heparin plasma
• Tube: Gold top
• Preparation: Collect between 7 and 11 am (peak level); repeat a low result, ideally fasting.

Reference range

Reference ranges differ between laboratories, methods and populations. Always use the range printed on your own lab report.

Causes of high values

• PCOS
• Androgen-secreting tumours
• Congenital adrenal hyperplasia
• Anabolic steroid or testosterone use

Causes of low values

• Primary or secondary hypogonadism
• Obesity and type 2 diabetes
• Hyperprolactinaemia
• Opioids and glucocorticoids
• Acute illness

Method

Immunoassay or LC-MS/MS (preferred for women and children)

Good to know

When SHBG is abnormal, calculate or measure free testosterone.

Related tests