A multicentre evaluation of the Boehringer Mannheim/Hitachi 704 analysis system

The selective multitest Boehringer Mannheim/Hitachi 704 analysis system was examined according to the ECCLS guidelines in a multicentre evaluation involving four laboratories. Ten routine parameters, covering most of the application settings of the instrument, were measured in the respective laboratory at temperatures 25, 30 or 37 degrees C. The trial lasted four months and gave more than 40,000 data. It yielded the following results: 1. Within the four laboratories the mean coefficients of variation for three control sera at different concentrations were found to be equal to or better than 1.6% for the within-run imprecision and 2.8% or better for the between-day imprecision. 2. No drift was observed during eight hours. 3. Because of the high linear measuring range a re-run analysis was seldom necessary. 4. Sample-related carry-over was not seen. Reagent-dependent carry-over was measured from cholesterol to uric acid and from triacylglycerols to lipase. Through modification of the cholesterol and triacylglycerol reagents, the carry-over effect was practically eliminated. 5. The recovery of the assigned values of control sera showed average values between 99 and 104%. For bilirubin, creatinine, creatine kinase and alanine aminotransferase some control sera showed deviations greater than 10%. 6. In all cases, regression analysis of the results obtained in comparisons of the present instrument with the Hitachi 705 or 737 yielded slopes close to unity with extreme values of 0.95 and 1.06. 7. During the entire evaluation period there was no malfunction or breakdown of the instruments. The evaluators came to the conclusion that the analytical performance as well as the reliability and practicability of the Hitachi 704 can be rated as excellent.