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HCG blood test - quantitative
Definition
A quantitative human chorionic gonadotropin (HCG) test measures the specific level of HCG in the blood. HCG is a hormone produced in the body during pregnancy.
Other HCG tests include:
Alternative Names
Serial beta HCG; Repeat quantitative beta HCG; Human chorionic gonadotropin blood test - quantitative; Beta-HCG blood test - quantitative; Pregnancy test - blood - quantitative
How the Test is Performed
Blood is drawn from a vein. The vein used is usually from the inside of the elbow or the back of the hand. The site is first cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.
Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.
Once the blood has been collected, the needle is removed. The puncture site is covered with an adhesive bandage to stop any bleeding.
How to Prepare for the Test
No special preparation is necessary.
How the Test Will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the Test is Performed
HCG appears in the blood and urine of pregnant women as early as 10 days after conception. Quantitative HCG measurement helps determine the exact age of the fetus. It can also diagnose abnormal preqnancies, such as ectopic pregnancies, molar pregnancies, and possible miscarriages. It is also used as part of a screening test for Down syndrome.
This test is also done to diagnose abnormal conditions not related to pregnancy that can raise HCG level.
Normal Results
HCG level rises rapidly during the first trimester of pregnancy and then slightly declines.
What Abnormal Results Mean
Higher-than-normal level may indicate:
- Normal pregnancy
- More than one fetus -- for example, twins or triplet
- Choriocarcinoma of the uterus
- Hydatidiform mole of the uterus
- Ovarian cancer
- Testicular cancer (in men)
Lower-than-normal levels may indicate:
- Fetal death
- Incomplete miscarriage
- Threatened spontaneous abortion (miscarriage)
- Ectopic pregnancy
Risks
There is very little risk in having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks of having blood drawn are slight but may include:
- Excessive bleeding
- Fainting or feeling light-headed
- Blood accumulating under the skin (hematoma)
- Infection (a slight risk any time the skin is broken)
References
Lee P, Pincus MR, McPherson RA. Diagnosis and management of cancer using serologic tumor markers. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 74.
Morrison LJ. General approach to the pregnant patient. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, PA: Elsevier Mosby; 2009:chap 175.
Webster RA. Reproductive function and pregnancy. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 25.
Reviewed By: Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Bellevue, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.
