Human Chorionic Gonadotropin (HCG)

Clinical Chemistry

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Description

hCG serves to maintain the corpus luteum during pregnancy to enable synthesis of progesterone and oestrogens that support the endometrium. hCG is secreted by the syncytiotrophoblast in pregnancy but may also be secreted from the pituitary, germ cell tumours, trophoblastic disease and nonreproductive tumours ( hepatobiliary, neuroendocrine ). hCG can be detected in maternal blood 7-9 days after conception and peaks around 8-10 weeks gestation. During early pregnancy levels double approximately every 48 hours. Slower doubling times are seen in ectopic pregnancy and threatened miscarriage. hCG levels fall during the second trimester and remain fairly steady until term. Following delivery, hCG falls with a half-life of 24 - 36 hours. A slower fall after delivery or miscarriage suggests retained products of conception. Gestational Trophoblastic Disease ( Hydatidiform mole or choriocarcinoma ): hCG may be extremely high ( into 7 figures ) and patient may present with hyperthyroidism due to weak TSH-like activity of hCG. Other hCG-producing tumours: many hCG-producing tumours also produce alpha fetoprotein ( AFP ).

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Indications

Diagnosis and monitoring of pregnancy ( normal and abnormal ), trophoblastic disease & hCG secreting tumours.

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Sample Type

Serum. SST/Gel, minimum 2 mL ( 1 mL separated serum ). Choriocarcinoma patients - Urine, random sample, plain bottle.

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Reference Range

Reference ranges are provided on the report. Alternatively, please contact the laboratory for current ranges.

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Turnaround Time

Serum within 24 hrs. Urine - within 3 working days

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Testing Frequency

Daily

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External Notes

If sending specimens from other laboratories, avoid multiple freeze-thaw cycles.

UCG RIA method detects all HCG variants (as necessary for monitoring Choriocarcinoma).

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Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.