Standardization of laboratory test in the JPHC study. Japan Public Health Center-based Prospective Study on Cancer and Cardiovascular Diseases.

The standardization committee has carried out standardization of 23 laboratories in the cohort area. They participated in the External Quality Control Survey by the Japan Medical Association. Most laboratories got A or B in evaluation criteria for most test items, but the results of AST, ALT and gamma-GTP were unsatisfactory. As for the lipid standardization, accuracy and precision of all 23 laboratories were satisfactory except for one. Close communication and collaborative study with reference laboratory improved the accuracy control.