title: Assessment of enzyme measurement procedures in China through a trueness verification program.
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.
authors.affiliation: 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.
authors.forename: Yufei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Beijing Hospital and National Center for Clinical Laboratories, Beijing Engineering Research Center of Laboratory Medicine, No. 1 Dahua Road, Dongcheng District, Beijing 100730, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Beijing Hospital and National Center for Clinical Laboratories, Beijing Engineering Research Center of Laboratory Medicine, No. 1 Dahua Road, Dongcheng District, Beijing 100730, China.
authors.forename: Haijian
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Beijing Hospital and National Center for Clinical Laboratories, Beijing Engineering Research Center of Laboratory Medicine, No. 1 Dahua Road, Dongcheng District, Beijing 100730, China.
authors.forename: Jiangtao
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Beijing Hospital and National Center for Clinical Laboratories, Beijing Engineering Research Center of Laboratory Medicine, No. 1 Dahua Road, Dongcheng District, Beijing 100730, China.
authors.forename: Tianjiao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Beijing Hospital and National Center for Clinical Laboratories, Beijing Engineering Research Center of Laboratory Medicine, No. 1 Dahua Road, Dongcheng District, Beijing 100730, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zeng
authors.affiliation: Beijing Hospital and National Center for Clinical Laboratories, Beijing Engineering Research Center of Laboratory Medicine, No. 1 Dahua Road, Dongcheng District, Beijing 100730, China.
authors.forename: Weiyan
authors.initials: W
authors.lastname: Zhou
authors.affiliation: 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.
authors.forename: Chuanbao
authors.initials: C
authors.lastname: Zhang
mesh_terms: D002681:China; D004796:Clinical Enzyme Tests; D006801:Humans; D010453:Peptide Synthases / Q000097:blood* / Q000378:metabolism; D005723:gamma-Glutamyltransferase / Q000097:blood* / Q000378:metabolism
chemical_list: D005723:gamma-Glutamyltransferase; D010453:Peptide Synthases; C019638:D-alanylalanine synthetase
keywords: Bias; Commutable material; Standardization; Traceability; Trueness verification program