Quality control in maternal serum prenatal screening in the second trimester / 中华检验医学杂志

ABSTRACT

Objective To analyze the features of quality management of maternal serum prenatal screening for Down syndrome in the second trimester and investigate the methods to establish and improve quality control system.Methods Prenatal screening and clinical data were collected for statistical analysis from 17 prenatal screening centers in Zhejiang Province from 2011 to 2012.The impacts of maternal age , weight, gestational age , specimen collection , the median values of serum markers selection and different analysis software on prenatal screening results for Down syndrome were analyzed respectively .Results Totally 417 347 and 463 846 prenatal screening cases were collected in 2011 and 2012 respectively.The maternal age of the entire province presented as a Gaussian distribution.The age distributions of different screening institutions were inconsistent , while maternal weight distributions were similar.The approach to determine gestational age was significantly different among screening institutions.Median MoM of the samples from the blood collection points was different from those of the main screening center.Median MoM-freeβ-hCG was positive bias , particularly the specimens from the blood collection points.After strengthening the control of temperature and time during samples transportation , Median MoM-free β-hCG of specimens from blood collection points became nearly equal to those of main screening center .Use of local median made the median MoM value closer to 1.0 in the centers with positive or negtive bias of the markers , which had little effect in detection rate and decreased the false positive rate and screening positive rate.Six more positive cases were detected by the Lifecycle software instead of 2T software in 213 followed-up positive cases, which means the Lifecycle software can improve the detection rate.Conclusions The impact of maternal age, weight, gestational age, specimen collection and other factors on screening performance should be taken into consideration when it evaluates the screening quality of different laboratory .The use of local medians is necessary in prenatal screening.Optimization of screening analysis software can reduce false negative rate.