hCG Test

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Also known as: Pregnancy test; qualitative hCG; quantitative hCG; beta hCG
Formal name: Human chorionic gonadotropin

At a Glance

Why Get Tested?

To confirm and monitor pregnancy or to diagnose trophoblastic disease or germ cell tumours

When to Get Tested?

As early as 10 days after a missed menstrual period (some methods can detect hCG even earlier, at one week after conception) or if a doctor thinks that your symptoms suggest ectopic pregnancy, a failing pregnancy, trophoblastic disease or germ cell tumours

Human chorionic gonadotrophin (hCG) is also tested as part of the prenatal screening program for Down’s syndrome.

Sample Required?

A urine sample collected first thing in the morning or a blood sample taken from a vein in the arm

Test Preparation Needed?

None needed; however, do not drink large amounts of fluid before collecting a urine sample for a pregnancy test because overly dilute urine may result in a false negative test result.

The Test Sample

What is being tested?

Human chorionic gonadotrophin (hCG) is a hormone produced in the placenta of a pregnant woman. A pregnancy test is a specific blood or urine test that can detect hCG and confirm or exclude pregnancy. The hormone can be detected 10 days after a missed menstrual period, the time period when the fertilised egg is implanted in the woman's uterus. With some methods, hCG can be detected even earlier, at one week after conception.

During the early weeks of pregnancy, hCG is important in maintaining function of the corpus luteum (which is formed from the ruptured ovarian follicle following ovulation). Production of hCG increases steadily during the first trimester of a normal pregnancy, peaking around the 10th week after the last menstrual cycle. Concentrations then fall slowly during the remainder of the pregnancy.

hCG is no longer detectable within a few weeks after delivery. hCG is also produced by some germ cell tumours and increased levels are seen in trophoblastic disease.

How is the sample collected for testing?

hCG is most commonly measured in urine, for confirmation or exclusion of pregnancy. The preferred specimen is a random urine sample collected first thing in the morning. hCG can also be measured in blood taken from a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

None needed; however, do not drink large amounts of fluid before collecting a urine sample for a pregnancy test because overly dilute urine may result in a false negative test result.

The Test

Common Questions

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.