A method of performing an optical measurement of an analyte in a processed biological sample using a cartridge, wherein the cartridge is operable for being spun around a rotational axis, wherein the cartridge comprises: - a support structure, wherein the support structure has a front face perpendicular to the rotational axis, wherein the rotational axis passes through the support structure; - a fluidic structure for processing a biological sample into the processed biological sample, wherein the fluidic structure comprises a sample inlet for receiving the biological sample, wherein the fluidic structure is formed by the support structure; - a measurement structure located on the front face, wherein the measurement structure is fluidically connected to the fluidic structure by a fluidic connection (403, 715), wherein the fluidic connection is formed by the support structure, wherein the measurement structure comprises at least one detection zone; - a rotatable lid covering the front face, wherein the rotatable lid is moveably attached to the support structure, wherein the rotatable lid is operable for being rotated about the rotational axis of the cartridge relative to the support structure, wherein the rotatable lid is operable for being rotated from a first position relative to the support structure to a second position relative to the support structure, wherein the rotatable lid has a sample inlet opening (202, 300), wherein the rotatable lid has a detection zone opening, wherein in the first position of the lid the sample inlet of the fluidic structure is aligned with the sample inlet opening and the measurement structure is covered by the rotatable lid, wherein in the second position of the lid the sample inlet of the fluidic structure is covered by the rotatable lid and the measurement structure is aligned with the detection zone opening; wherein the method comprises: - placing the biological sample into the sample opening; - rotating the rotatable lid from the first position to the second position; - controlling the rotational rate of the cartridge to process the biological sample into the processed biological sample using the fluidic structure; - controlling the rotational rate of the cartridge to allow the processed biological sample to flow into the measurement structure; and - performing the optical measurement on the measurement structure with an optical instrument. - a support structure, wherein the support structure has a front face perpendicular to the rotational axis, wherein the rotational axis passes through the support structure; - a fluidic structure for processing a biological sample into the processed biological sample, wherein the fluidic structure comprises a sample inlet for receiving the biological sample, wherein the fluidic structure is formed by the support structure; - a measurement structure located on the front face, wherein the measurement structure is fluidically connected to the fluidic structure by a fluidic connection (403, 715), wherein the fluidic connection is formed by the support structure, wherein the measurement structure comprises at least one detection zone; - a rotatable lid covering the front face, wherein the rotatable lid is moveably attached to the support structure, wherein the rotatable lid is operable for being rotated about the rotational axis of the cartridge relative to the support structure, wherein the rotatable lid is operable for being rotated from a first position relative to the support structure to a second position relative to the support structure, wherein the rotatable lid has a sample inlet opening (202, 300), wherein the rotatable lid has a detection zone opening, wherein in the first position of the lid the sample inlet of the fluidic structure is aligned with the sample inlet opening and the measurement structure is covered by the rotatable lid, wherein in the second position of the lid the sample inlet of the fluidic structure is covered by the rotatable lid and the measurement structure is aligned with the detection zone opening; - placing the biological sample into the sample opening; - rotating the rotatable lid from the first position to the second position; - controlling the rotational rate of the cartridge to process the biological sample into the processed biological sample using the fluidic structure; - controlling the rotational rate of the cartridge to allow the processed biological sample to flow into the measurement structure; and - performing the optical measurement on the measurement structure with an optical instrument.