Background: Maternal serum triple marker screening has been covered by the medical insurance system in Korea since December 2004. The number of tests is on the increase, but an external quality control program and a basic survey have not been established yet. The aim of this study was to port the survey of prenatal screening tests.
Methods: Three different quality control specimens were prepared using the sera obtained from 100 women who were in the 15th to 20th week of pregnancy and visited Asan Medical Center during May 2005. We assumed that the three specimens belonged to the first day of 15 weeks, third day of 16 weeks, and second day of 19 weeks, respectively, and sent them to 10 laboratories. Nine laboratories replied to the survey. We analyzed concentrations, multiples of medians (MoMs), and risk estimates.
Results: The coefficients of variance of MoM were 32.1-32.6% for alpha-fetoprotein, 15.3-19.8% for unconjugated estriol, 6.3-12.5% for human chorionic gonadotropin, and 12.9-18.2% for inhibin-A. In Down syndrome risk estimation for specimen-2, six of the eight laboratories that used the triple test reported the screen positive, but two laboratories reported negative. Three of five laboratories using the quadruple test reported the screen positive, and two laboratories reported negative. In case of neural tube defect, all laboratories except one reported all specimens the screen negative. In case of Edward syndrome, all laboratories reported all specimens the screen negative.
Conclusions: Since MoMs and risk estimates showed a wide variation among the participating laboratories in this survey, an external quality control and the standardization of the variables seemed warranted.