CARTRIDGE AND OPTICAL MEASUREMENT OF AN ANALYTE WITH SAID CARTRIDGE

The invention provides for a method of performing an optical measurement (1132) of an analyte in a processed biological sample using a cartridge (100). The cartridge is operable for being spun around a rotational axis (108). The method comprises: placing the biological sample into a sample inlet (112); controlling (1200) the rotational rate of the cartridge to process a biological sample into the processed biological sample using a fluidic structure (110); controlling (1202) the rotational rate of the cartridge to allow the processed biological sample to flow from the measurement structure inlet to an absorbent structure via a chromatographic membrane, and performing (1204) an optical measurement of a detection zone (122) on the chromatographic membrane with an optical instrument. An inlet air baffle reduces evaporation of the processed biological sample from the chromatographic membrane during rotation of the cartridge