BACKGROUND: We evaluated the analytical performances of Diasys reagents manufactured by Diasys Diagnostic Systems (Holzheim, Germany) with Hitachi 747. METHODS: We evaluated AST, ALT, ALP, gamma-GT, calcium, and glucose. Only two tests were adapt-ed to different methods from the current ones: the photometric test using the arsenazo III for calci-um, the kinetic colorimetric test according to Szasz/Persijin using l-gamma-glutamyl-3-carboxy-4-nitranilide as a substrate for gamma-GT. Precision, interference, linearity, and method comparisons were evaluated by NCCLS guidelines. RESULTS: The coefficient of variation (CV) of total precision was less than 6.8% in all items. Preci-sions and linearities of all items were acceptable. Correlation coefficients were more than 0.9884 and all items showed excellent agreement compared to the current reagents in the reportable range. We could not find any significant interference for six test items up to 750 mg/dL triglyceride, 50 mg/dL hemoglobin, and 20 mg/dL bilirubin, except that the latter ALT showed a negative bias by more than 5 mg/dL of bilirubin. CONCLUSIONS: Diasys reagents showed high precision, linearity and correlation in comparison to the current reagents. So we conclude that these reagents are good for routine clinical use with Hitachi 747.