[Evaluation of the technique of CKMB assay using Ektachem (500 and 700)]

The aim of this study was to compare the dry-chemistry CKMB Ektachem method to a liquid immunoinhibition method (Merck/Cobas Bio) and to the electrophoretic method (Helena France), both on patients (n = 95) and control (4 specimens from different commercial origin) sera. The Ektachem method was found linear in the range tested (7 to 97 U/l). Within run imprecision tested with low, medium and high control sera were satisfying (CV 3-4%) as well as between run imprecision (CV < 10%), for CKMB activities of at least 30 U/l. As compared to the liquid immunoinhibition method (Merck), the results of patient sera were very close but slightly lower (y = 0.97x-1; r = 0.74; y = Ektachem, x = Merck). As compared to the electrophoretic method, the Kodak Ektachem method showed a specificity of 74% and a sensitivity of 85% (n = 95). A close agreement (r = 0.73) between these two methods was obtained for samples with a total CK activity at least 3 times over the upper limit of normal range. We therefore conclude that the Kodak Ektachem CKMB method allows a rapid and easy determination of CKMB activity for samples undergoing total CK activity 3 times over the upper limit of normal range. Like all liquid immunoinhibition methods, the Kodak Ektachem method shows some lack of specificity and does not show a better concordance with the electrophoretic method than does the Merck/Cobas Bio method.