Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
The presence of hCG in plasma at times other than pregnancy can indicate abnormal trophoblastic tissue or a tumour secreting the hormone ectopically. hCG is used to diagnose and monitor patients with germ cell tumours (testicular cancer in men and extragonadal germ cell tumours) CNS involvement can be assessed by measuring CSF and serum levels.
Specimen container paediatric:
Serum-Plain tube
Specimen container adult:
Serum-SST
Minimum volume paediatric:
0.5 mL blood
Minimum volume adult:
1 mL blood
Sample stability:
Unseparated sample: unknown
Separated sample:
1 day at 15-25C,
7 days at 2-8C,
1 year at -20C
Add on test:
This test cannot be added on. Please contact the duty biochemist to discuss.
Interpretation:
Ovarian germ cell tumours constitute less than 1% of all ovarian malignancies, differentiated along either embryonic or extra-embryonal pathways, only the embryonal or choriocarcinomas actively secrete hCG. Conversely, 95% of testicular tumours are of germ cell origin with 16% of seminomas and all choriocarcinomas secreting HCG. However it is important to monitor germ cell tumours with both AFP and hCG as changes in composition may occur requiring changes in therapy. Chemotherapy is often based on slight changes in marker levels.
Reference ranges:
– Males: <2 IU/L
– Females:Pre-menopausal: <5 IU/L
Peri-menopausal: <7 IU/L
Post-menopausal: <10 IU/L
Factors affecting result:
A high dose hook effect may occur at concentrations >750,000 IU/L
Heterophilic antibodies can interfere with immunoassays.
Other info:
Plasma- Lithium Heparin also acceptable