I am 15 weeks pregnant with my first child and the doctor asked if I wanted a triple screen test. What exactly is this and should I get it? – Sara
Most expectant women will be offered a maternal blood-screening test around weeks 15-20 of their pregnancy. Also known as a "triple marker" test, the triple screen test measures the levels of a protein produced by the fetus as well as two pregnancy-produced hormones in the mother's blood. This test can reveal the chance that a mother is carrying a fetus with neural tube defects or Down syndrome.
The test is sometimes called a quadruple screen (or marker) when the level of an additional substance, called inhibin-A, is also measured. Keep in mind that these are screening tests and only show the possibility of a problem existing — they don't provide a definitive diagnosis, and don't catch all abnormalities. However, if results are positive that a problem could exist, other diagnostic tests can then be performed.