A Quad Screen, also called a Maternal Serum Analyte Screen, is a group of blood tests that check for substances linked with certain birth defects such as Down Syndrome, neural tube defects, Edwards Syndrome, and other related birth defects.

This test is done during the 15th to 21st week of your pregnancy. If you get an abnormal test result, your pregnancy will be further evaluated. Keep in mind that this test has many false positives.