Abstract: A method is provided for determining the concentration of an analyte in a sample which comprises: a) performing an electrochemical test comprising: (i) contacting the sample with an electrochemical cell comprising at least two electrodes; and (ii) obtaining at least one group of three or more measurements of an electrochemical parameter from the cell, wherein each measurement in each at least one group is obtained at a different time; b) deriving from said at least one group of three or more measurements a single value that is indicative of the time-dependent behavior of the measured parameter; c) comparing the single value indicative of the time-dependent behavior of the measured parameter with a pre-determined range of acceptable time-dependent behaviors; d) determining whether the test is acceptable based on the result of said comparison; e) optionally repeating the above-mentioned steps; and 0 determining the concentration of the analyte from the measurements obtained from the acceptable test or acceptabl

Abstract: A method for the determination of the amount of cholesterol in high density lipoproteins in a high density lipoprotein containing sample, said method comprising reacting the sample with a surfactant which preferentially reacts with high density lipoproteins in the sample, said surfactant being selected from hydroxyethyl glucamide derivatives and N-acyl-N-methyl glucamine derivatives, and measuring the amount of cholesterol in the high density lipoproteins, for example using an electrochemical technique.