Definition of HCG blood test - quantitative:

A quantitative human chorionic gonadotropin (HCG) test measures the specific level of HCG in the blood. HCG is a hormone produced during pregnancy.

See also:

• HCG urine test
• HCG blood test - qualitative

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.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is 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, while 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 measurements can help to determine the exact age of the fetus and can diagnose abnormal preqnancies, such as ectopic pregnancies, molar pregnancies, and potential miscarriages. It is also used as part of a screening test for Down Syndrome.

This test is also done to diagnose abnormal conditions unrelated to pregnancy that can raise HCG levels.