Yufei Wang1, Jing Wang2, Haijian Zhao2, Jiangtao Zhang2, Tianjiao Zhang2, Jie Zeng2, Weiyan Zhou2, Chuanbao Zhang3. 1. Beijing Hospital and National Center for Clinical Laboratories, Beijing Engineering Research Center of Laboratory Medicine, No. 1 Dahua Road, Dongcheng District, Beijing 100730, China; Chinese Academy of Medical Sciences and Peking Union Medical College, No. 9 Dongdan Santiao Road, Beijing 100005, China. 2. Beijing Hospital and National Center for Clinical Laboratories, Beijing Engineering Research Center of Laboratory Medicine, No. 1 Dahua Road, Dongcheng District, Beijing 100730, China. 3. Beijing Hospital and National Center for Clinical Laboratories, Beijing Engineering Research Center of Laboratory Medicine, No. 1 Dahua Road, Dongcheng District, Beijing 100730, China. Electronic address: cbzhang@nccl.org.cn.
Abstract
BACKGROUND: Since 2003, the National Center for Clinical Laboratories (NCCL) has organized a network of reference laboratories and several survey programs to improve standardization in China. METHODS: We analyzed the 2015 trueness verification program to assess the status of enzyme measurement standardization. Commutable serum-based materials were prepared and sent to 10 reference laboratories to assign target values for 2 enzymes (alanine aminotransferase-pyridoxal phosphate [ALT-pp] and γ-glutamyltransferase [GGT]) using IFCC reference measurement procedures. RESULTS: Analytical performance was assessed for compliance to 3 indexes: trueness (bias), imprecision (CV), and accuracy (total error). Of the 250 participating laboratories, about half (≥124) used heterogeneous systems. More laboratories met the tolerance limit of imprecision than of trueness or accuracy. Except at the lowest concentration, the CV pass rates were >90% for the 2 enzymes. The optimal performance criterion derived from biological variation yielded pass rates for total error (ALT 77%, GGT 80%) that were higher than for bias (ALT 63%, GGT 73%). CONCLUSIONS: PT/EQA results for commutable samples can be used to assess trueness against reference measurement procedures. Despite global and national standardization programs, bias remains a critical limitation of current enzyme measurement procedures in China.
BACKGROUND: Since 2003, the National Center for Clinical Laboratories (NCCL) has organized a network of reference laboratories and several survey programs to improve standardization in China. METHODS: We analyzed the 2015 trueness verification program to assess the status of enzyme measurement standardization. Commutable serum-based materials were prepared and sent to 10 reference laboratories to assign target values for 2 enzymes (alanine aminotransferase-pyridoxal phosphate [ALT-pp] and γ-glutamyltransferase [GGT]) using IFCC reference measurement procedures. RESULTS: Analytical performance was assessed for compliance to 3 indexes: trueness (bias), imprecision (CV), and accuracy (total error). Of the 250 participating laboratories, about half (≥124) used heterogeneous systems. More laboratories met the tolerance limit of imprecision than of trueness or accuracy. Except at the lowest concentration, the CV pass rates were >90% for the 2 enzymes. The optimal performance criterion derived from biological variation yielded pass rates for total error (ALT 77%, GGT 80%) that were higher than for bias (ALT 63%, GGT 73%). CONCLUSIONS: PT/EQA results for commutable samples can be used to assess trueness against reference measurement procedures. Despite global and national standardization programs, bias remains a critical limitation of current enzyme measurement procedures in China.