|
Synonyms |
|
Human
Chorionic Gonadotrophin (HCG)
|
|
Clinical
Indications |
|
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 48 hours.
For a complete miscarriage,
the hCG should halve during this period.
If the serum hCG is over 5,000 U/L, it should be
possible to confirm intrauterine pregnancy by
transvaginal (not abdominal) ultrasound scan.
|
|
Request
Form |
|
Combined
Pathology Blood form (Yellow/Black or Blue for GP's)
|
|
Availability |
|
On
request if specific criteria met.
|
|
Specific
Criteria |
|
Suspected
ectopic pregnancy. See protocol
for management of patients with suspected ectopic
pregnancy.
|
|
Turnaround
Time |
|
Same Day
|
|
Specimen |
|
Serum
|
|
Volume |
|
1
ml
|
|
Container |
|
Yellow
top (SST) tube
|
|
Causes for
Rejection |
|
Unlabelled
sample
|
|
Reference
Range |
|
Non-pregnancy
levels <
5 U/mL. Pregnancy levels:
|
time
since LMP |
mean |
range |
|
week
4 |
1,110 |
40
to 4,480 |
|
week
5 |
8,050 |
270
to 28,700 |
|
week
6 |
29,700 |
3,700
to 84,900 |
|
week
7 |
58,800 |
9,700
to 120,000 |
|
week
8 |
79,500 |
31,100
to 184,000 |
|
week
9 |
91,500 |
61,200
to 152,000 |
|
Week
10 |
71,000 |
22,000
to 143,000 |
|
Week
14 |
33,100 |
14,300
to 75,800 |
|
Week
19 |
20,900 |
3,600
to 56,600 |
|
|
|
|
|
|
Interpretation |
|
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.
|
|