title: Status of internal quality control for thyroid hormones immunoassays from 2011 to 2016 in China.
abstract: BACKGROUND
  Internal quality control (IQC) plays a key role in the evaluation of precision performance in clinical laboratories. This report aims to present precision status of thyroid hormones immunoassays from 2011 to 2016 in China.
  
  
  METHODS
  Through Clinet-EQA reporting system, IQC information of Triiodothyronine and Thyroxine in the form of free and total (FT3, TT3, FT4, TT4), as well as Thyroid Stimulating Hormone (TSH) were collected from participant laboratories submitting IQC data in February, 2011-2016. For each analyte, current CVs were compared among different years and measurement systems. Percentages of laboratories meeting five allowable imprecision specifications (pass rates) were also calculated. Analysis of IQC practice was conducted to constitute a complete report.
  
  
  RESULTS
  Current CVs were decreasing significantly but pass rates increasing only for FT3 during 6 years. FT3, TT3, FT4, and TT4 had the highest pass rates comparing with 1/3TEa imprecision specification but TSH had this comparing with minimum imprecision specification derived from biological variation. Constituent ratios of four mainstream measurement systems changed insignificantly. In 2016, precision performance of Abbott and Roche systems were better than Beckman and Siemens systems for all analytes except FT3 had Siemens also better than Beckman. Analysis of IQC practice demonstrated wide variation and great progress in aspects of IQC rules and control frequency.
  
  
  CONCLUSIONS
  With change of IQC practice, only FT3 had precision performance improved in 6 years. However, precision status of five analytes in China was still unsatisfying. Ongoing investigation and improvement of IQC have yet to be achieved.
authors.affiliation: National Center for Clinical Laboratories/Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, National Center of Gerontology, Beijing, China.|Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: Shishi
authors.identifier: http://orcid.org/0000-0002-0764-7902
authors.initials: S
authors.lastname: Zhang
authors.affiliation: National Center for Clinical Laboratories/Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, National Center of Gerontology, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: National Center for Clinical Laboratories/Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, National Center of Gerontology, Beijing, China.
authors.forename: Haijian
authors.initials: H
authors.lastname: Zhao
authors.affiliation: National Center for Clinical Laboratories/Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, National Center of Gerontology, Beijing, China.
authors.forename: Falin
authors.initials: F
authors.lastname: He
authors.affiliation: National Center for Clinical Laboratories/Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, National Center of Gerontology, Beijing, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Zhong
authors.affiliation: National Center for Clinical Laboratories/Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, National Center of Gerontology, Beijing, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Yuan
authors.affiliation: National Center for Clinical Laboratories/Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, National Center of Gerontology, Beijing, China.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Wang
mesh_terms: D002681:China; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000592:standards*; D011786:Quality Control; D015203:Reproducibility of Results; D013963:Thyroid Hormones / Q000097:blood*
chemical_list: D013963:Thyroid Hormones
keywords: internal quality control; performance specification; precision; thyroid hormones immunoassays