Serum Pregnancy Test
Alternate Names : Quantitative Pregnancy Test, Blood, HCG Quantitative Serum Test, Human Chorionic Gonadotropin Level Blood Test, Quantitative Serum Beta-HCG, Quantitative Beta HCG, Serum
What do the test results mean?
Greater than normal levels of HCG may indicate:
a tumor of the placenta with death of the fetus
multiple pregnancy, such as twins or triplets
ovarian cancer and other types of cancer in some cases
a normal pregnancy
blood or protein in the urine, which can interfere with the result
use of medications to prevent seizures, drugs to treat Parkinson's syndrome, or phenothiazine drugs, such as chlorpromazine, by the mother
Lower-than-normal HCG levels may indicate:
a miscarriage, or abortion. The miscarriage may only be threatened and never happen, may be happening at the time of the test, or may have already occurred. Further testing can determine which of these, if any, is the case.
use of diuretics, or "water pills," by the mother, which can interfere with the result
The test may fail to detect HCG even when a woman is pregnant if the test is done too early. It takes at least 7 days after fertilization for the test to become positive. In most cases, by the time a woman has missed her period, the test will be positive if she is pregnant.
A normal pattern of HCG levels over time is expected in a healthy pregnancy. The level of HCG increases throughout the first trimester, then gradually decreases over time. In the first trimester, a woman may have this test done repeatedly to see if the level rises normally. If it doesn't, the pregnancy is often considered in trouble. After childbirth, miscarriage, or abortion, the level should quickly decrease to zero.
This test can also be measured repeatedly if there is a tumor or cancer of the placenta or ovary in some cases. This test can only be used if the tumor or cancer caused the level of HCG to be high. This can happen in some tumors that actually make HCG. After treatment of the tumor or cancer, the level should go back down to zero. If it doesn't, the tumor or cancer may still be present in the body and more treatment may be needed.