Triple test

The Triple screen measures serum levels of AFP, estriol, and beta-hCG, with a 70% sensitivity and 5% false-positive rate.

It is complemented in some regions of the United States, as the Quad screen (adding inhibin A to the panel, resulting in an 81% sensitivity and 5% false-positive rate for detecting Down syndrome when taken at 15–18 weeks of gestational age)[3] and other prenatal diagnosis techniques, although it remains widely used in Canada[4] and other countries.

The Triple test can be understood as an early predecessor to a long line of subsequent technological improvements.

[5] While the triple test can be performed at any point between 15 and 21.9 weeks of gestation, the highest detection rate for open neural defects is given by a test performed between 16 and 18 weeks of gestation.

[7] The triple test measures the following three levels in the maternal serum:[8] The levels may indicate increased risk for certain conditions or may be benign: An estimated risk is calculated and adjusted for the expectant mother's age;[9] if she is diabetic; if she is having twins or other multiples, and the gestational age of the fetus.