The hormone Human chorionic gonadotropin (hCG) is produced by the placenta during pregnancy. During the early stages of pregnancy, the hCG level in the blood increase, this test detects the level and is used to confirm pregnancy.
The course of hCG is as follows, during the early weeks of pregnancy the hormone supports the functioning of the corpus luteum. Levels usually keeps increasing during the first trimester peaking at week 10. Levels then fall slowly for the duration of the pregnancy and are usually undetectable within weeks after delivery.
In some cases, the pregnancy occurs outside of the uterus (ectopic pregnancy) and the level of hCG increase more slowly. This requires medical attention and more frequent measurements of the exact level (Quantitative test) might be required to make the diagnosis.
The hCG tests is a qualitative test that gives a positive or negative result by detecting the presence of hCG.
Quantitative hCG testing measures the actual amount of hCG present in the blood and is usually used to confirm the pregnancy after a positive hCG test in the blood or urine test. It is also used to diagnose ectopic pregnancy, fetal abnormalities, monitoring failing pregnancies or miscarriages.
Pregnancy can be confirmed reliably by a blood hCG test from 10 days after a missed menstrual period. Repeat testing within 1 day is recommended if pregnancy is still suspected but the initial test was negative.
Quantitative blood hCG tests are usually ordered by a medical practitioner to identify an ectopic pregnancy or to monitor a woman following a miscarriage.