Abstract: A system (1) for infectious disease screening. The system is for use with an assay device (2) which incorporates an ultrasonic transducer for generating ultrasonic waves to lyse cells in a biological sample. The system (1) comprises a frequency control module which is configured to control the ultrasonic transducer (49) to oscillate at an optimum frequency for cell lysis, a PCR arrangement (16) which is configured to receive and amplify the DNA from the sample; and a detection arrangement (70) which is configured to detect the presence of an infectious disease in the amplified DNA and to provide an output which is indicative of whether or not the detection arrangement (70) detects the presence of an infectious disease in the amplified DNA.