Double Marker (Double Screen) Test: Also known as the first trimester screening test, 11-14 week test, double marker test or nuchal translucensy (NT) scan, this test involves an ultrasonographic examination at 11-14 weeks of gestation and assessing the risk of several fetal genetic anomalies. By means of laboratory screening tests on the mother’s blood sample the risk of Down syndrome is examined. After the test is done, the test results are explained in detail to the parents.
Nuchal translucensy is the accumulation of fluid at the back of the baby’s neck. Using ultrasound, it is measured whether the nuchal fold thickness of the baby is within the normal range. If the NT measurement is higher than it should be, it indicates that both chromosomal and structural disorders are possible.
Triple Screen test: It is the second trimester screening test used to determine whether there are common genetic anomalies in the fetus. The triple screen test, also called Kettering test or Bart test, is a blood screening test that checks alpha-fetoprotein (AFP), chorionic gonadotropin (hCG) and estradiol. Unlike the double screen test, the risk of neural tube defects can also be monitored.
Quad Screen Test: It is a test performed for the same purpose as the triple screen test, but yields more precise results compared to the triple screen test. In addition to the B-hCG free estriol and AFP levels evaluated in the triple test, the addition of Inhibin-A value in the quad screen test increases the test’s success rate. In the quad screen test, the rate of detecting whether the baby has Down syndrome is 80%. The most accurate test that can be recommended for expectant mothers who have not had the double screen test, NT and combined tests performed in the first trimester is the quad test.
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