Abstract: A method for determining the amount of an analyte in a sample is provided, the method including the steps of detecting signals resulting from reaction of captured analyte with detection molecules, applying a mathematical transformation function to the signal results, and using a computer to mathematically model a biphasic standard curve of analyte concentration vs transformed detected signal using an equation. A method for modelling calibration data, a computer programmed to mathematically model a biphasic standard curve of analyte concentration vs transformed detected signal, and a kit of parts for determining the amount of an analyte in a sample is also provided.