Dry Reagent Technology. Kodak Ektachem 700 XR in Clinical Enzymology

Abstract

The comparability of results for enzyme activity concentrations estimated with the methods recommended by the Scandinavian Committee on Enzymes(SCE) or the subcommittee on Enzymes of the European Committee for Clinical Laboratory Standards(ECCLS), and with the Kodak Ektachem methods, are discussed. As the Ektachem system in principle uses the IFCC methods at 37°C as a reference, the results compare reasonably well for the alanine amino-transferase(ALAT), aspartate aminotransferase(ASAT), creatine kinase(CK) and γ-glutamyltransferase(GT). The Ektachem reference method for lactate dehydrogenase(LD) is in principle the SCE method. The reasons for lower values with the SCE method are discussed. The interference on the Ektachem alkaline phosphatase (ALP) method from high concentrations of methotrexate(MTX) in serum, is shown. Results from our investigations on the interference by heparin in enzyme determinations on Ektachem are given.

The problems with CK determinations in cancer patients regarding myocardial diseases are well known. When CK-BB is present in serum, the CK-B concentration is apparently lower using the Ektachem CK method than with use of the CK-MB slide, probably relating to the fact that chelator is omitted from the CK slide, while EGTA is supplied in the CK-MB slide. The user's dependence on the manufacturer for the choice of methods and the quality of the reagents, makes it important for laboratories and die Kodak Company to collaborate with the intention to continously improve the Ektachem methodologies. The future possibilities of this technology seem to be nearly unlimited.

Key Words:

• Enzyme methods
• Kodak Ektachem 700 XR
• matrix effects
• methotrexate interference
• heparin interference
• enzyme intermethod comparison