Evaluation of the Kodak Ektachem glucose and urea methods

An evaluation of the Kodak Ektachem glucose and urea methods is described. Aspects evaluated included precision, linearity, accuracy, correlation with routine methods, interferences (haemoglobin, bilirubin, protein, dextran, lipaemia, ethylene-diamine tetraacetic acid, fluoride/oxalate, and heparin), and carryover. Stability and batch-to-batch variation in glucose and urea reagents were also investigated. The performance of the Ektachem glucose and urea methods was shown to be as satisfactory as conventional analytical methods. The requirement to reconstitute control serum samples in a bicarbonate diluent in order to obtain accurate results presents problems for the analysis of lyophilised specimens circulated by external quality assessment schemes. The complex calibration model and the significance of variation in the calibration parameters need further explanation. The Ektachem methods are designed specifically for use with human serum. However, the methods performed satisfactorily with cerebrospinal fluid, pleural effusions, and animal serum but not with urine.