First-Trimester Screening for Down's Syndrome

To the Editor: Wapner and colleagues (Oct. 9 issue) 1 describe implementation of the first-trimester combined test for trisomies 21 and 18 in 8514 women with a singleton pregnancy. They compare the performance of the Down's syndrome screening test (a detection rate of 79 percent with a false positive rate of 5 percent) with published estimates for the second-trimester triple and quadruple tests but not with the integrated test, although they cite the article describing the integrated test. 2 They overlook the superior screening performance of the integrated test, which uses late first-trimester and early second-trimester markers together to obtain one screening . . .