A method for measuring the amount of an analyte in a sample, the method comprising the steps of: a. providing a detection assembly, said detection assembly comprising: i. a source of electromagnetic radiation, ii. a means for detecting electromagnetic radiation, and iii. a container containing a sample-free liquid, said container being positioned between the source of electromagnetic radiation and the means for detecting electromagnetic radiation such that applied electromagnetic radiation from the source may radiate through the container from the source to the detection means, or alternatively such that applied electromagnetic radiation from the source may result in the emission of electromagnetic radiation from the liquid in the container to the detection means, b. adding a sample to the sample-free liquid in the container, c. optionally adding one or more reagents, d. providing a measurement of electromagnetic radiation at time T 0 , e. optionally adding one or more reagents, f. providing a measurement of electromagnetic radiation at time T 1 , g. optionally providing one or more further sample measurements of electromagnetic radiation, wherein steps b - d may be performed in any order, the method being characterised in that the sample and the liquid in the container are subjected to at least one mixing step (m) performed by oscillating the detection assembly in a circular or ellipse motion by vortexing, whereby the positioning of the container relative to the source and the means is constant during said mixing step. a. providing a detection assembly, said detection assembly comprising: i. a source of electromagnetic radiation, ii. a means for detecting electromagnetic radiation, and iii. a container containing a sample-free liquid, said container being positioned between the source of electromagnetic radiation and the means for detecting electromagnetic radiation such that applied electromagnetic radiation from the source may radiate through the container from the source to the detection means, or alternatively such that applied electromagnetic radiation from the source may result in the emission of electromagnetic radiation from the liquid in the container to the detection means, i. a source of electromagnetic radiation, ii. a means for detecting electromagnetic radiation, and iii. a container containing a sample-free liquid, said container being positioned between the source of electromagnetic radiation and the means for detecting electromagnetic radiation such that applied electromagnetic radiation from the source may radiate through the container from the source to the detection means, or alternatively such that applied electromagnetic radiation from the source may result in the emission of electromagnetic radiation from the liquid in the container to the detection means, b. adding a sample to the sample-free liquid in the container, c. optionally adding one or more reagents, d. providing a measurement of electromagnetic radiation at time T 0 , e. optionally adding one or more reagents, f. providing a measurement of electromagnetic radiation at time T 1 , g. optionally providing one or more further sample measurements of electromagnetic radiation, wherein steps b - d may be performed in any order, the method being characterised in that the sample and the liquid in the container are subjected to at least one mixing step (m) performed by oscillating the detection assembly in a circular or ellipse motion by vortexing, whereby the positioning of the container relative to the source and the means is constant during said mixing step. <EOS>