Differences in second trimester risk estimates for trisomy 21 between Maglumi X3/Preaccu and Immulite/Prisca systems

Abstract

Objectives Maternal serum alpha-fetoprotein (AFP), human chorionic gonadotropin (HCG) or free βHCG, and unconjugated estriol (uE3) concentrations are used to screen trisomy 21 in the second trimester. The performance of different analytical platforms has an impact on individual risk estimates. The aim of this study is to compare the multiple of median (MoM) values and risk estimates generated by Maglumi X3 analyzer/Preaccu software with the Immulite 2000 XPi device/Prisca software. Methods 164 pregnant women (including 20 pregnants with risk estimates above ≥1 in 250 for trisomy 21) analyzed with both platforms. Results Passing–Bablok indicated proportional bias (0.75 [95 % CI 0.70 to 0.82]) between AFP MoMs and both systematic (−0.20 [95 % CI –0.33 to −0.05]) and proportional (1.25 [95 % CI 1.06 to 1.44]) differences between the HCG/free βHCG MoMs, respectively. No significant differences (p=0.070) were present between calculated individual risks by both of the programmes (estimated median risk with Immulite/Prisca system was 1 in 1890 and 1 in 1220 with Maglumi X3/Preaccu system). The triple test result for three pregnant women was negative with the Prisca program, it was positive with the Preaccu. Conclusions Second trimester screening performance of Maglumi X3/Preaccu system achieves comparable performance. Determining regional median values before using will provide more accurate and reliable results.