The Optics Check Cassette performs a check on the optical system of the LDX analyzer based on known reflectance values encoded in the cassette. It is recommended that the optics check should be run once a day before patient samples are tested as well as after the LDX analyzer has been moved or serviced. The Optics Check Cassette is reusable until its expiration date. When not in use, it should be stored at room temperature in the case provided.