In the fight against emerging public health threats, early diagnosis of infectious diseases is crucial. And in poor and remote areas of the globe where conventional medical tools like microscopes and cytometers are unavailable, rapid diagnostic tests, or RDTs, are helping to make disease screening quicker and simpler. RDTs are generally small strips on which blood or fluid samples are placed. Specific changes in the color of the strip, which usually occur within minutes, indicate the presence of infection. Different tests can be used to detect various diseases, including HIV, malaria, tuberculosis and syphilis.