QUAD screen. Historically performed between 16-20 weeks, the maternal serum quadruple screen (quad) is likely to fall by the wayside now that cell-free fetal dna can actually be tested from the maternal blood (maternit21 and others). Quad is a screening - not diagnostic - test.
Quad screen. This is a blood test usually done between 15 and 20 weeks of pregnancy. It tries to calculate the risk of the baby having down's syndrome, another genetic disorder called trisomy, or open spina bifida. It cannot tell you for sure if the baby has these, just if you are at increased risk. There are definitely some false negatives (rare) and false positives (common).
Quad Screen. This non-invasive prenatal screening blood (serum) test is done around 12 weeks gestation to see if the fetus may have down's syndrome (trisomy 21) or trisomy 18. It is often combined with a transvaginal ultrasound for better accuracy. This test is not diagnostic. If the screening test is worrisome, then an amniocentesis is usually recommended. Read more...