DPP Typhoid System. The test cassette and DPP Micro Reader with holder and typhoid test device are shown. (A and B) The DPP Typhoid System consists of a test cassette, which consist of a sample path and reagent path which intersect in the analyte detection area labeled 1 (LPS), 2 (HlyE), and C (control) (A) and the DPP Micro Reader, a portable, battery-powered instrument that displays a numerical intensity value for the test lines (B).