title: Status of External Quality Assessment on Tumor Markers in China.
abstract: BACKGROUND
  The nationwide external quality assessment (EQA) of tumor markers in China has been launched for years. The quality of the performance of Chinese clinical laboratories on tumor markers is partly reflected through analysis of EQA results. This report presents an 8-year EQA result of the six most common tumor markers from 2006 to 2013.
  
  
  METHODS
  Ten freeze-dried EQA samples were distributed to participants every year. Satisfactory performance was defined as scores of more than 80% of acceptable responses with the evaluation criterion of ± 25%. The robust coefficient of variability (CV) between laboratories and percentage difference against the target value of each sample were also calculated by year.
  
  
  RESULTS
  A total number of 1154 laboratories submitted results in 2013, which was more than threefold of 2006. The proportion of laboratories with satisfactory performance showed an overall rising trend over the years and was up to 95% for the second survey in 2013. The overall decrease of robust CV was observed for all analytes including alpha fetoprotein (AFP), carcinoembryonic antigen (CEA), total prostate specific antigen (t-PSA), cancer antigen 125 (CA 125), cancer antigen 15-3 (CA 15-3), and cancer antigen 19-9 (CA 19-9) except for CEA, which exhibited a rise followed by a flat trend. The percentage difference narrowed gradually and was less than 2% in 2013.
  
  
  CONCLUSIONS
  The 8-year EQA results showed a significant enhancement of degree of harmonization of tumor markers in China. However, standardization among various testing systems and improvement of harmonization has yet to be achieved.
authors.forename: Yaling
authors.initials: Y
authors.lastname: Xiao
authors.forename: Chuanbao
authors.initials: C
authors.lastname: Zhang
authors.forename: Haijian
authors.initials: H
authors.lastname: Zhao
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Falin
authors.initials: F
authors.lastname: He
authors.forename: Kun
authors.initials: K
authors.lastname: Zhong
authors.forename: Shuai
authors.initials: S
authors.lastname: Yuan
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Wang
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D018394:CA-125 Antigen / Q000378:metabolism; D018395:CA-19-9 Antigen / Q000378:metabolism; D002272:Carcinoembryonic Antigen / Q000378:metabolism; D002681:China; D015925:Cryopreservation; D006801:Humans; D007753:Laboratories / Q000592:standards*; D008565:Membrane Proteins / Q000378:metabolism; D018396:Mucin-1 / Q000378:metabolism; D009369:Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011785:Quality Assurance, Health Care; D011786:Quality Control; D015203:Reproducibility of Results; D000509:alpha-Fetoproteins / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D018394:CA-125 Antigen; D018395:CA-19-9 Antigen; D002272:Carcinoembryonic Antigen; C451759:MUC16 protein, human; D008565:Membrane Proteins; D018396:Mucin-1; D000509:alpha-Fetoproteins; D017430:Prostate-Specific Antigen