Double Marker Test:
A double marker screening test is one that is conducted in the first trimester, primarily, between the 10th to 13th week of pregnancy. A blood sample is taken to measure the levels of β hCG (human chorionic gonadotropin hormone) and the PAPP – A (pregnancy-associated plasma protein). This test is used to detect the likelihood of having a child with Down syndrome. It is commonly done in women over the age of 35, as there is an increased chance of having a child with Down syndrome as the maternal age increases.
Advantages and Disadvantages of Double Marker Test:
Since this test is conducted in the first trimester, it is an early screening test that helps to assess genetic conditions. This gives you ample time to decide on further tests and further screening tests that can be done as the pregnancy progresses. It is fairly accurate in diagnosing Down syndrome and similar genetic conditions.
While it is accurate, triple and quadruple screening test provides more accuracy as they analyze more markers within the blood. The accuracy increases up to 88 – 90% with a quadruple screening test. Tests conducted later in pregnancy always give a much better picture of any fetal abnormalities.
The main disadvantage, however, would be the cost of the procedure. It can be expensive for some considering physician fees, hospital bills, prenatal supplements and other tests required during the course of pregnancy.