Human Chorionic Gonadotrophin (HCG)
Ectopic pregnancy should be considered and serum hCG measured in
any young woman with unexplained abdominal pain whether or not she
has missed a period or had abnormal vaginal bleeding.
Results should not be interpreted in isolation but in the
context of clinical features
Serum hCG can be positive within 7-10 days of conception.
If an ectopic pregnancy or a miscarriage is suspected, two
specimens should be taken 48 hours apart. For an intrauterine
pregnancy, the hCG should double during this period.
Generally the rate of increase is slower for ectopic pregnancies,
although for early ectopic pregnancies the hCG can still double in
For a complete miscarriage, the hCG should halve during this
If the serum hCG is over 5,000 U/L, it should be possible to
confirm intrauterine pregnancy by transvaginal (not abdominal)
Request on ICE
On request if specific criteria met.
Suspected ectopic pregnancy.
Causes for Rejection
Unlabelled or incorrectly labelled sample
Non-pregnancy levels < 5 U/mL.
Levels may remain raised for up to 2 weeks following childbirth
and up to 4 weeks following abortion.
Patients receiving courses of hCG (e.g. Pregnyl) or hMG
(Perganol) may give false positive results for a few days after
administration of the drug.