Status of internal quality control in early pregnancy serum prenatal screening in China: an analysis based on six sigma metrics
10.3760/cma.j.cn113903-20230921-00223
- VernacularTitle:我国早孕期血清学产前筛查室内质控现状：基于六西格玛管理体系的分析
- Author:
Jinming ZHANG
1
;
Falin HE
Author Information
1. 北京医院（国家老年医学中心、中国医学科学院老年医学研究院）、国家卫生健康委员会临床检验中心（北京市临床检验工程技术研究中心）室间质评室，北京 100730
- Keywords:
Prenatal diagnosis;
Serology;
Biomarkers;
Quality control
- From:
Chinese Journal of Perinatal Medicine
2024;27(9):729-734
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To evaluate the quality level of early pregnancy serum screening in China.Methods:Information on the coefficient of variation, bias, quality control (QC) rules, and testing methods from 576 laboratories participating in the 2022 early pregnancy serum screening inter-laboratory proficiency testing program by the National Health Commission Clinical Laboratory Center was collected. Serological screening indicators included free human chorionic gonadotropin β subunit (β-hCG), total β-hCG, and pregnancy-associated plasma protein A (PAPP-A). Six Sigma (σ) management was used to assess the quality level of the laboratories and the rationality of QC rules.Wilcoxon test was used to evaluate whether different testing time and methods affected the Sigma level.Results:A total of 119 laboratories tested total β-hCG, 457 laboratories tested free β-hCG, and 565 laboratories tested PAPP-A. Seventeen laboratories tested only one marker, 553 laboratories tested two markers, and six laboratories tested three markers. There was no statistically significant difference in sigma levels for the same analyte tested in May and September. The proportion of free β-hCG reaching 6σ was the highest at 71.9% (567/788); although total β-hCG had the lowest proportion reaching 6σ at 53.4% (103/193), it also had the lowest proportion below 3σ at 3.1% (6/193). Early pregnancy serum prenatal screening mainly involved five reagents and primarily used chemiluminescence and time-resolved fluorescence methods (free β-hCG was only tested using chemiluminescence). Laboratories using time-resolved fluorescence had overall higher sigma levels [total β-hCG: 9.56 (7.01-13.22) vs. 5.84 (4.36-9.12), W=53 114.00; PAPP-A: 9.04 (6.40-12.62) vs. 5.71 (4.22-8.15), W=75 752.00; both P<0.001] compared to those using chemiluminescence. The proportion of QC rules conforming to Westgard sigma rules ranged from 16.1% (31/193) to 19.6% (166/846). Among them, the proportion of laboratories with overly lenient QC rules was 24.8% (210/846) to 32.1% (62/193), and the proportion with overly strict QC rules was 51.8% (100/193) to 55.6% (470/846). Conclusion:The overall QC level of prenatal screening laboratories in China is fine, but there is still room for improvement in the setting of QC rules.
