Multianalyte Conventional Reference Material (MacRM): A Useful Tool for Nationwide Standardization of Laboratory Measurements for Medical Care-A Model Study in Japan.

BACKGROUND: The Japanese Committee for Clinical Laboratory Standards (JCCLS) has developed a multianalyte conventional reference material (MacRM) for nationwide standardization of laboratory measurements. METHODS: To prepare the MacRM, pooled sera were obtained from healthy Japanese individuals. Target values of the pooled sera for 30 analytes were assigned on the basis of the measurement results of 45 certified clinical laboratories whose calibration was verified by measuring certified reference materials (CRMs) provided by the National Institute of Standards and Technology, the Institute for Reference Materials and Measurements, and JCCLS. Commutability of MacRM was assessed by comparison with results for 150 individual inpatients at Fukuoka University Chikushi Hospital. Survey samples were prepared by essentially the same method for MacRM but without target values. The survey samples were used to assess agreement among 165 laboratories that used various assay kits and platforms calibrated with the MacRM. RESULTS: The commutability of MacRM was confirmed for 30 analytes with sera from 150 individual patients. The imprecision (CV) of measurements of survey samples (high and low concentrations) among the 165 laboratories was 0.4%-10.0%. Twenty-six of 30 analytes were within the goals for interinstitutional allowable bias. An aliquot of MacRM stored frozen at -80 °C remained stable for ≥4 years. CONCLUSIONS: The MacRM was successfully applied as a calibrator to achieve nationwide standardization for 30 analytes measured by 165 laboratories that used various methods from different manufacturers.

Nationwide multicenter study aimed at the establishment of common reference intervals for standardized clinical laboratory tests in Japan.

BACKGROUND: The Japanese Association of Medical Technologists (JAMT) sought to establish common reference intervals (RIs) applicable nationwide in Japan for 27 serum constituent analytes for which certified reference materials are available and nine analytes frequently measured in routine tests. More than 100 laboratories certified for metrological traceability collaborated in the recruitment, sampling, and measurement of analytes for the establishment of RIs. No previous attempt has been made to establish RIs by such a large number of laboratories. The allowable limits of trueness and intermediate precision based on the JAMT criteria were applied to the reference values measured by these laboratories, and measured values within the allowance limits were used to establish RIs. METHODS: Reference individuals included 5748 healthy volunteers aged 18-65 years who were engaged in medical care-related work based on the CLSI guidelines. After secondary exclusion of individuals in whom abnormal values were detected in basic routine test items and adjustment for the distribution of age and gender, 3371 reference individuals were chosen in the parametric determination of RIs. Employing the three-level nested ANOVA, between-laboratory, -region, -sex, and -age variations were evaluated. RESULTS: No significant difference was noted in between-region variations in any item. Results of ANOVA revealed between-sex and -age variations in 14 and 15 analytes, respectively. Based on these results of variation, RIs were established with and without partition by sex. CONCLUSIONS: Since no between-region variation was detected in reference values among accuracy-certified core laboratories, RIs applicable nationwide were established.

Reference intervals of red blood cell parameters and platelet count for healthy adults in Japan.

Although it is known that red blood cell (RBC) parameters and platelet count depend on ethnicity and sex, their reference intervals in healthy Asian populations are limited. The aim of this study was to establish reference intervals for RBC parameters and platelet count for healthy adults in Japan. A total of 750 healthy adults (447 women and 303 men; median age 40 years (18-67 years) at seven Japanese centers who participated in regular medical checkups entered this study. Their RBC parameters and platelet count were measured using automated hematocytometers. The reference intervals of the RBC parameters and platelet count according to sex in healthy adults were determined. There was an age-specific decrease in RBC counts and an age-specific increase in mean corpuscular volume in men. This study emphasizes the need to consider sex and age in the clinical use of reference intervals of RBC parameters.