We describe a rapid, kinetic, fixed-time method for determining serum total cholesterol by use of cholesterol esterase, cholesterol oxidase, and the indicator reaction with peroxidase, 4-aminophenazone, and phenol. On addition of the competitive inhibitor 3,4-dichlorophenol the Michaelis constant of cholesterol oxidase is apparently increased, which extends the linear relation between absorbance change and cholesterol concentration to 20.7 to 25.9 mmol/L, depending on the analyzer being used. For calibration, a single standard is used. Total analysis time is in the range of 80 to 210 s. Incubation temperature is 25 degrees C or 37 degrees C. The single-reagent procedure has been adapted to three different centrifugal analyzers and to the Eppendorf ACP 5040 analyzer. It yields precise and accurate results and is insensitive to potential interferences.

We have developed a kinetic fixed-time approach for the quantitative determination of serum glucose by use of the hexokinase/glucose-6-phosphate dehydrogenase method. To achieve a large measuring range, we have apparently increased the Michaelis constant of glucose-6-phosphate dehydrogenase through addition of the competitive inhibitor ATP. By this means, serum samples with glucose concentrations up to 55.5 mmol/1 could be analyzed without pre-dilution. The method has been adapted to the ENI GEMSAEC analyzer and to the LKB 2086 Mark II analyzer. It yielded satisfactory results with regard to precision. A comparison of the kinetic procedure with the manual end-point method showed good agreement. No interferences from hemoglobin, bilirubin, or lipemia have been observed.Kinetische Bestimmung von Glucose im Serum mit der Hexokinase/Glucose-6-phosphat-Dehydrogenase-Methode

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Summary:The use of a new monoclonal enzyme immuiioassay (EIA) for the carcinoembryonic antigen' (CEA) (Enzymun^Test® CEA) was eväluated in a multi-centre study. Fifteen different laboratories participated in the study. Data fröm the investigation were analysed in terms of precision, sensitivity, specificity and correlation with other test methods. The intra-assay coefficient of Variation was between 1.3% at 23.0 g/l CEA and 13.9% at l^g/l CEA. Iiiter-assay reproducibility ranged from 3.6% to 19.2%. The apparent sensitivity of the new EIA for CEA was approx. 0.5 g/l CEA. The findings indicate that lipaemic and haemolytic sera and samples taken from icteric, rheumatic and dialysis patients did not have any influence on the results. There was no evidence that drugs commonly used in the treatment of carcinoma patients have any influence on the assay results. A good correlation between the new EIA for CEA and six other CEA enzyme "immunoassay or radioiinmunoassay methods was registered. These results seem to be of significance in particiflar for the monitoring of therapy for carcinoma patients. The new EIA for CEA exhibits a high degree of sensitivity, specificity and reproducibility.

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