title: The Asian project for collaborative derivation of reference intervals: (2) results of non-standardized analytes and transference of reference intervals to the participating laboratories on the basis of cross-comparison of test results.
abstract: BACKGROUND
  The 2009 Asian multicenter study for derivation of reference intervals (RIs) featured: 1) centralized measurements to exclude reagent-dependent variations; 2) inclusion of non-standardized analytes (hormones, tumor makers, etc.) in the target; and 3) cross-check of test results between the central and local laboratories. Transferability of centrally derived RIs for non-standardized analytes based on the cross-check was examined.
  
  
  METHODS
  Forty non-standardized analytes were centrally measured in sera from 3541 reference individuals recruited by 63 laboratories. Forty-four laboratories collaborated in the cross-check study by locally measuring aliquots of sera from 9 to 73 volunteers (average 22.2). Linear relationships were obtained by the major-axis regression. Error in converting RIs using the regression line was expressed by the coefficient of variation of slope b [CV(b)]. CV(b) <10% was set as the cut-off value allowing the conversion. The significance of factors for partitioning RIs was determined similarly as in the first report.
  
  
  RESULTS
  Significant sex-, age-, and region-related changes in test results were observed in 17, 15, and 11 of the 40 analytes, respectively. In the cross-comparison study, test results were not harmonized in the majority of immunologically measured analytes, but their average CV(b)s were <10% except for total protein, cystatin C, CA19-9, free thyroxine, and triiodothyronine. After conversion, 74% of centrally derived RIs were transferred to each local laboratory.
  
  
  CONCLUSIONS
  Our results point to the feasibility of: 1) harmonizing test results across different laboratories; and 2) sharing centrally derived RIs of non-standardized analytes by means of comparative measurement of a set of commutable specimens.
authors: Department of Clinical Laboratory Sciences, Yamaguchi University Graduate School of Medicine, Minami-Kogushi 1-1-1, Ube 755-8505, Japan. ichihara@yamaguchi-u.ac.jp
authors: Kiyoshi
authors: K
authors: Ichihara
authors: Ferruccio
authors: F
authors: Ceriotti
authors: Mori
authors: M
authors: Kazuo
authors: Yang-Yang
authors: YY
authors: Huang
authors: Yoshihisa
authors: Y
authors: Shimizu
authors: Haruki
authors: H
authors: Suzuki
authors: Masami
authors: M
authors: Kitagawa
authors: Kazuyoshi
authors: K
authors: Yamauchi
authors: Sadao
authors: S
authors: Hayashi
authors: Chia-Chun
authors: CC
authors: Tsou
authors: Yoshikazu
authors: Y
authors: Yamamoto
authors: Shigeo
authors: S
authors: Ishida
authors: Linda
authors: L
authors: Leong
authors: Michitaka
authors: M
authors: Sano
authors: Hwan Sub
authors: HS
authors: Lim
authors: Akira
authors: A
authors: Suwabe
authors: Hee-Yeon
authors: HY
authors: Woo
authors: Keiya
authors: K
authors: Kojima
authors: Yoshio
authors: Y
authors: Okubo
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D044466:Asian People; D014408:Biomarkers, Tumor / Q000097:blood*; D001798:Blood Proteins / Q000032:analysis*; D055316:Cystatin C / Q000097:blood*; D005260:Female; D006801:Humans; D008074:Lipoproteins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012737:Sex Factors; D013963:Thyroid Hormones / Q000097:blood*
chemical_list: D014408:Biomarkers, Tumor; D001798:Blood Proteins; D055316:Cystatin C; D008074:Lipoproteins; D013963:Thyroid Hormones