A triple or multiple marker test is an important blood test to rule out three substances in the placenta – human chorionic gonadotropin (hCG), alpha-fetoprotein (AFP) and Estriol. It is also called multiple marker screening and AFP Plus. It is a vital indicator of a woman with chance of having multiple pregnancy or baby with genetic defects. However, its results are inaccurate.
This test is usually done for pregnant women between 15-20 weeks of pregnancy. It is an alternative to quadruple marker screen test.
How it works?
A Triple Market helps identify the levels of the following substances in a pregnant woman:
Alpha-fetoprotein (AFP): Alpha-fetoprotein is a protein secreted by the growing fetus. A high level of AFP indicates presence of genetic defects such as neural tube defects.
Human chorionic gonadotropin (hCG): Human chorionic gonadotropin is a hormone present in the placenta. Low hCG levels may indicate future pregnancy complications such as ectopic pregnancy or miscarriage. While high hCG levels usually means chances of molar pregnancy or multiple pregnancy.
Estriol : Estrogen produced by the fetus and placenta. Low estriol levels means your baby may have Down Syndrome.
Who needs a Triple Marker Test?
- Women at 35 years of age or more.
- Either of the partners with a history of birth defects.
- Either of the partners diagnosed with diabetes.
- Couple already having a child with birth defects.
- Couples with too much exposure to radiations.
- Couples diagnosed with viral infection during pregnancy.
If you have negative indicators on their triple marker screen test then abnormal results are good indicators for further testing and preventing birth defects. Also in abnormal results, an amniocentesis or chorionic villi sampling (CVS) test may be recommended.
In an amniocentesis test, a sample of amniotic fluid is extracted using a needle. It helps identify genetic disorders or possible fetal threats. A CVS test is done between 8-12 weeks of pregnancy and aminocentesis test is done between 14-16 weeks of pregnancy. A CVS test involves taking chorionic tissue from the placenta from vaginal or USG guided through abdomen.