Among the most commonly used malaria diagnostic tests is the rapid diagnostic test (RDT), which detects malaria antigens from a drop of blood. Whilst RDTs are small and cheap, they’re invasive and new strains of the parasite have evolved that can escape RDT diagnosis. Now, engineers have developed new diagnostic technology – a cytophone – which doesn’t require a blood draw. About the size of a desktop printer, the cytophone uses lasers and ultrasound to detect infected red blood cells in the vein on a patient’s hand or forearm. The cytophone works by detecting hemozoin, a byproduct of all malaria parasites from their consumption of hemoglobin for energy. When hemozoin absorbs a certain amount of the laser energy, it heats up and expands, generating ultrasound waves that indicate malaria infection within the red blood cell. In a trial of 20 adults in Cameroon with symptomatic malaria, the cytophone prototype performed as well as current point-of-care diagnostic methods.