The triple screen test is a maternal screening test. It screens for three specific substances: AFP, hCG, and Estriol.
AFP : This is an alpha -fetoprotein that is produced by the fetus.
hCG : This is human chorionic gonadotropin is a hormone produced by the placenta.
Estriol : Estriol is an estrogen produced by both the fetus and the placenta.
How is the triple screen test performed ?
This test involves drawing blood from the mother. It takes about 5 to 10 minutes. The blood sample is then sent to the lab for viewing. The results may take a couple of days.
Are there any risks ?
There are no risks or side effects to the mother or baby. You may just experience discomfort from the site your blood being drawn.
Who needs the triple screen test ?
The test is performed between 15 to 20 weeks of gestation. It is most accurate during the 16th to 18th week of pregnancy. All pregnant women should be offered this test but it is highly recommended for the following women.
- age 35 years and older
- have a family history of birth defects
- had viral infections during pregnancy
- possible use of harmful prescription medication or drugs during pregnancy
- have been exposed to high levels of radiation
What does the triple screen test look out for ?
This test measures high and low levels of AFP as well as abnormal levels of hCG and estriol. The results are combined with maternal weight, age, ethnicity and gestation age of pregnancy to assess the possibility of a genetic disorder.
High levels of AFP may indicated that the baby has neural tube defects such as spina bifida. However one of the most common causes of a high AFP level is wrong calculation of the gestational age of the pregnancy.
Low levels of AFP and abnormal levels of hCG and estriol may indicate that the developing baby has Down syndrome , Edwards syndrome or any type of chromosomal abnormalities.
The result of a triple screen test may be used to identify pregnancies that are more advanced than thought or multiple pregnancies.
What do the results mean ?
It is important to note that this test is a screen test, not a diagnostic test. It tells you the possibility of the baby having a genetic disorder. The triple screen test is also known to have a high percentage of false positive results.
Abnormal results may warrant further testing to be able to make a diagnosis. A second triple screen test followed by a high definition ultrasound may be done. If the results still come back abnormal, you may need a more invasive test such as an amniocentesis to confirm diagnosis.
Further testing is optional. However, it provides you the opportunity to make a diagnosis and get potential intervention such as surgery that may be available for the baby. It may also help to prepare emotionally and physically for taking care of a child with special needs.
Some individual may opt out if further testing due to personal, moral, or religious reasons. It is important to discuss the benefits and risk of this test with your health care provider.
Triple screening in pregnancy. American Academy of Family Physicians. http://familydoctor.org/familydoctor/en/pregnancy-newborns/fetal-health/triple-screening-in-pregnancy.html. Accessed January 2, 2015
Triple or Quad Screening for Birth Defects. WebMD.http://www.webmd.com/a-to-z-guides/triple-or-quad-screening-for-birth-defects-topic-overview. Accessed January 2, 2015