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Quad screen Test
The quad-screen test can help your healthcare provider determine if you might be carrying a baby with Down syndrome. This blood test can also help rule out other problems in your pregnancy, such as neural-tube defects.

The quad screen test is the same as the triple screen, with the addition of a fourth measurement: your inhibin-A level. This fourth measurement raises the sensitivity of the standard triple-screen test by 20% in determining whether a fetus has Down syndrome.
The quad-screen test is able to identify 79% of those fetuses with Down syndrome. It has a false-positive result 5% of the time.