Comparison of two solid phase chemistry systems: Reflotron and Ektachem DT 60

Solid phase chemistry can be used for clinical analysis at the bedside, and it is even applicable to whole blood. We compared precision, accuracy, method linearity, and practicability of two solid phase chemistry analysers. Reflotron (Boehringer Mannheim, W. Germany) and Ektachem DT 60 (Eastman Kodak Co, USA). Eight analytes, glucose, cholesterol, triacylglycerols, urea, uric acid, alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyltransferase were investigated. The precision of both instruments was good. Coefficients of variation for within run and day to day precision were below 10% for all analytes. Methods were compared by analysing 88 to 105 patients sera for each investigated analyte on Reflotron, on Ektachem DT 60 and on a wet chemistry reference instrument. Linear regression analysis showed good agreement between wet chemistry and solid phase chemistry results. Coefficients of correlation (r) ranged from 0.957 to 0.999. Reflotron and Ektachem are desk top analysers. Reflotron is the smaller instrument. Currently, it offers 9 analytes and rapid single test performance. Whole blood can be used for all tests. Test strips can be stored at room temperature. Ektachem DT 60 has a modular design, and 22 analytes are available. Series of up to 100 tests per hour are possible. Whole blood can be used for the preparation of glucose and haemoglobin test slides. The slides must be deep frozen for prolonged storage. Reflotron may be suitable for the physician's office, Ektachem for small laboratories. The problem of quality control has not yet been satisfactorily solved for either instrument, as only analyser-specific control specimens can be used. Reagent costs of solid phase chemistry tests are high, especially when large test series are performed. Operation of both instruments requires well trained personnel.