Sex Hormone Binding Globulin (SHBG)
- Sex hormone binding globulin (SHBG) is a protein synthesized by the liver which binds tightly to the steroids testosterone, oestradiol and DHT and transports them in the blood in an inactive form.
- SHBG levels are indicated in the investigation of hirsutism in women and for infertility, reduced libido or erectile dysfunction in men, particularly when androgen levels are within normal ranges and this does not fit the clinical picture.
- Increased SHBG levels can be seen in anorexia, pregnancy, ageing, growth hormone deficiency, androgen deficiency, hyperthyroidism, liver disease, hyperprolactinaemia, active porphyria and also with oestrogens.
- Decreased SHBG levels can be seen in obesity, hyperinsulinaemia, hypothyroidism and growth hormone excess, as well as with glucocorticoids, androgens, progestins. It can also be familial.
- In the investigation of hyperandrogenism in adult women, SHBG is often assayed in conjunction with total testosterone. From these results the free androgen index (FAI) can then be calculated to give an estimate of bioavailable testosterone. This calculation is not appropriate in males.
- If patient on high dose biotin therapy (>5mg/day) collect sample at least 8 hours after the last dose.
For adults, blood taken into a 5mL gold top gel tube (or rust top for the Acute Unit)
For children, blood taken into a 3.5mL rust top gel tube
Send at ambient temperature to the laboratory. If unavoidable, samples can be stored refrigerated overnight.
Relevant clinical details including the reason for testing.
SHBG samples are processed once a week at GRH. The turnaround time is less than 10 days.
|< 50 years old
|> 50 years old
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