HCG (quantitative)

How the Test is Performed:
Blood is drawn from a vein ( venipuncture ), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to distend (fill with blood). A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the tourniquet is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding .

How to Prepare:
No special preparation is necessary.

How it Feels:
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 .

Risks:
  • excessive bleeding
  • fainting or feeling lightheaded
  • hematoma (blood accumulating under the skin)
  • infection (a slight risk any time the skin is broken)
  • multiple punctures to locate veins



Why this Test is Performed:
Quantitative HCG measurements can allow precise prediction of the age of the fetus. It is also used when an abnormal condition that can elevate HCG level is suspected.

A pregnancy test is usually based on detection of HCG, which is secreted by the trophoblast after the ovum is fertilized. HCG appears in the blood and urine of pregnant women as early as 10 days after conception. HCG has a similar to function to LH in stimulating secretion of estrogen and development of the placenta. However, HCG may also be elevated in abnormal circumstances in men as well as women.

Normal Values:
Greater than 0.05 U/ml if you are pregnant is normal.
Levels vary with gestational age during pregnancy .

Note: U/ml = units per milliliter

Abnormal Results:
Greater-than-normal levels may indicate:

Lower-than-normal levels may indicate:



Cost:
The costs are:
$65 for a quantitative serum beta-HCG test
$45 for a repeat quantitative serum beta-HCG test
$103 for serial quantitative serum beta-HCG tests, 2 tests usually within 48 hours

Special Considerations:
Drugs that can decrease HCG measurements include diuretics and promethazine.

Drugs that can increase HCG measurements include anticonvulsants, antiparkinsonian drugs, phenothiazine, and promethazine.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.