Proficiency testing of maternal serum prenatal screening in second trimester in China, 2015

Prenatal screening and diagnosis is important for the detection of birth defects and genetic diseases. The nationwide proficiency testing (PT) of maternal serum prenatal screening in second trimester in China has been launched since 2003 and partly reflected the performance of screening laboratories. This study analysed the 2015 PT results to examine the performance of clinical laboratories and different platforms.

Fifteen lyophilized samples with different concentrations divided into three panels, were distributed to 613 clinical laboratories in 2015. Acceptable performance was defined as scores more than 80% of acceptable responses with the evaluation criterion of ± 30%. The robust coefficient of variation (CV) was also analysed. Chi-square (χ2) test was used to compare the acceptable performance while Kruskal-Wallis test and Mann-Whitney test were applied to compare the robust CV among analytes and mainstream platforms.

Overall, 605, 61, 214, 416, 303 laboratories submitted effective results for alpha fetoprotein (AFP), total human chorionic gonadotropin (t-hCG), β-hCG, unconjugated estriol (uE3) and free β-hCG. The acceptable performances of AFP (μg/L), AFP (KIU/L), t-hCG, β-hCG, uE3, and free β-hCG were 98.45%, 99.24%, 95.58%, 98.72%, 94.50%, and 98.66%, respectively. The χ2 test indicated significant differences existed in the acceptable performances among different analytes and platforms for uE3. Kruskal-Wallis test and Mann-Whitney test suggested the robust CV differed significantly in different analytes and platforms.

The majority of results were acceptable. However, further effort is needed to achieve the standardization and harmonization among analytes and various platforms, particularly for uE3.