Triple Check or Quad Screen Testing in Pregnancy

November 07, 2009

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Triple Check or Quad Screen Testing in Pregnancy

by Marjorie Greenfield, M.D.
reviewed and revised by Marjorie Greenfield, M.D.

The triple check test, sometimes called the triple screen, is an optional blood test (done on the mother) that can indicate an increased risk of two sorts of problems for the baby:

Down syndrome (and some other chromosome problems)
Spina Bifida (a problem where the spine hasn't fused closed properly.)

Other problems where a body cavity is exposed may also be detected. Recently an additional parameter has been added to the triple check test, changing the test to a quad screen. While the exact measurements are different, the concept is the same.

What is measured?
In the triple check, three chemistry tests are obtained from the mother's blood: hCG (a pregnancy hormone), estriol (an estrogen made by the placenta) and alpha-feto-protein (AFP, a protein in the blood of the fetus). Hence the name "triple check." In the quad screen an additional marker is measured, inhibin A(a glycoprotein made by the placenta). The results of these tests, plus the mother's age, mother's weight, and the gestational age of the fetus are then fed into a computer, and out pops an assessment of the risks (as described above) for this pregnancy. Accurate standards for these test results are not available until about 16 weeks gestation.

What the screen tells you
The triple check and quad screen are only a screening tests. The results come back as a statement of risk level.

For the risk of Down syndrome, it comes back as a number. A 1:5000 risk of Down Syndrome would be a very low risk, and not require further testing; A 1:10 risk would be considered high, and an amniocentesis would be recommended. Even with a high risk level like 1:10, the chances are good (in this case 90%) that the baby will not have Down Syndrome. An abnormal result on the test only means that more testing is indicated.
For the risk of spina bifida, and other open body cavity problems, the results are reported as "normal" (no further testing recommended) or "increased" (further testing is recommended.) The next step is a level two ultrasound, which allows a detailed look at the fetal anatomy. If that result isn't clear, amniocentesis is sometimes recommended.

An abnormal test does not automatically mean an unhealthy baby
Remember that most babies with abnormal tests are actually doing just fine. There is a big overlap between the results from healthy babies and the results of fetuses with problems. In order to be sure that all the fetuses with these problems are identified, and that the appropriate definitive testing is done, a lot of people carrying normal healthy fetuses go through a scare, and get more testing done such as amniocentesis or in-depth ultrasound.

In the future there may be other tests offered for risk screening. Scientists are searching for other blood chemistries to add or substitute into the current screening procedures, to make it more accurate for identifying fetuses at risk.


RELATED INFORMATION

			Routine Glucose Screening in Pregnancy
			What Ultrasound Can Show You During Pregnancy
			Fetal Assessment
			Genetic Testing in Pregnancy
			Moms-to-Be Testing

Created October 03, 2000
Reviewed and revised August 25, 2004

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