A pregnancy test measures a hormone called human chorionic gonadotropin (HCG). HCG is a hormone produced during pregnancy. It appears in the blood and urine of pregnant women as early as 10 days after conception.
See also:
A pregnancy test may be performed using blood or urine. There are two types of blood pregnancy tests:
The blood test is done by drawing a single tube of blood and sending it to a laboratory. You may wait anywhere from a few hours to more than a day to get the results.
The urine HCG test is usually performed by placing a drop of urine on a prepared chemical strip. It generally takes 1 to 2 minutes for a result.
The urine test involves normal urination into a cup. The serum tests involve drawing blood through a needle and into a tube. Any discomfort you might feel from the blood draw will only last a few seconds.
This test may be done to:
HCG levels rise rapidly during the first trimester of pregnancy and then slightly decline.
HCG levels should double every 48 hours in the beginning of a pregnancy. HCG levels that do not rise appropriately may indicate a problem with your pregnancy. Some problems associated with an abnormally rising HCG level include miscarriage and ectopic (tubal) pregnancy.
Extremely high levels of HCG may suggest a molar pregnancy or more than one fetus -- for example, twins.
Your health care provider will understand the significance of your HCG levels, and he or she should discuss the levels with you.
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Reviewer Info: Linda Vorvick, MD, Seattle Site Coordinator, Lecturer, Pathophysiology, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine; and Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Redmond, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.; ADAM Health Illustrated Encyclopedia, 10/28/2008 |