At a Glance
Why Get Tested?
Testing for human chorionic gonadotropin levels is done to diagnose and monitor:
When to Get Tested?
If you think you may be pregnant, a blood test for hCG may be positive as early as one week after conception, while a urine test, such as the tests you can do at home, may be positive at around the time of the first missed menstrual period. A doctor may wish to check your hCG level if you have fallen pregnant but you are having problems with the pregnancy, such as symptoms or signs of an ectopic pregnancy or miscarriage. The doctor may also check hCG levels if he or she thinks your symptoms suggest trophoblastic disease or a germ cell tumour.
A urine sample collected first thing in the morning or a blood sample drawn 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 pregnancy testing as very dilute urine may result in a false negative test result.
The Test Sample
What is being tested?
hCG is a protein 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 pregnancy. This hormone can be detected by a blood test as early as one week after conception or by a urine test at around the time of the first missed menstrual period.
During the early weeks of pregnancy, hCG is important in maintaining function of the corpus luteum (the mass of cells that forms from a mature egg). Production of hCG increases steadily during the first trimester, peaking around the 10th week after the last menstrual cycle. Levels then fall slowly during the remainder of the pregnancy. hCG is no longer detectable within a few weeks of delivery.
If something goes wrong with the pregnancy, the level of hCG may be higher or lower than usual. In the case of an ectopic pregnancy, the hCG may be lower than usual and, if a woman miscarries, the level of hCG will fall quickly. If a woman develops trophoblastic disease, the hCG level may be higher than expected.
hCG is also produced by some germ cell tumours.
How is the sample collected for testing?
When a test for hCG is done to see if a woman is pregnant, it may be done as a urine test or as a blood test from blood drawn from a vein in the arm. The urine test should be done on a urine sample collected first thing in the morning.
When a test for hCG is done on a pregnant woman to help diagnose problems with the pregnancy, it should be done as a blood test.
When a test for hCG is done on a male or female to test for a germ cell tumour, it should be done as a blood test.
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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.