Double marker test is screening blood test in pregnancy. It is usually done between 9 and 13 weeks. This test is done for those who suffer from down’s syndrome. It is detection of pre-birth conditions of the fetus. This test detects any kind of chromosomal abnormalities that might occur after the conception occurs. This is not completely unusual as it occurs in every 700 births. This test is important for women who gets pregnant after 35 as probability of abnormality in unborn is usually for elderly pregnant women. It is advisable that all pregnant women should go through this test so that she is sure that the baby is completely normal.