How the Test is Performed

Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is 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, and the puncture site is covered to stop any bleeding.

How to Prepare for the Test

No special preparation is usually necessary.

How the Test Will Feel

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the Test is Performed

Most often, this test is performed to determine if you are pregnant or not. The serum HCG level may also be high in women with certain types of ovarian tumors or men with testicular tumors.

Normal Results

• The test is negative if you are not pregnant.
• The test is positive if you are pregnant.

What Abnormal Results Mean

If your serum HCG is positive and you do not have a pregnancy properly implanted in the uterus, it may indicate:

• Ectopic pregnancy
• Miscarriage
• Testicular cancer (in men)
• Trophoblastic tumor
• Hydatidiform mole
• Ovarian cancer

Risks

There is very little risk involved with 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 associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Considerations

False positive tests may occur when certain hormones are increased, such as after menopause or when taking hormone supplements.

A pregnancy test is considered to be about 98% accurate. When the test is negative but pregnancy is still suspected, the test should be repeated in 1 week.

Alternative Names

Beta-HCG in blood serum - qualitative; Human chorionic gonadotrophin - serum - qualitative; Pregnancy test - blood - qualitative; Serum HCG - qualitative; HCG in blood serum - qualitative

References

Webster RA. Reproductive function and pregnancy. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: Saunders Elsevier; 2006:chap 25.

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. 21st ed. Philadelphia, Pa: Saunders Elsevier; 2006: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: Mosby Elsevier; 2009:chap 175.

Updated: 4/21/2012

Reviewed by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; 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.