Gazelle is an inexpensive, portable, and easy-to-use diagnostic device that provides affordable, accurate testing to new populations at sites where it is needed most. The compact, rugged, battery-operated in vitro diagnostic device is used inexpensively, with no cold chain requirements, by entry level healthcare workers in areas with limited access, resources, or electricity. Patient information and results are captured digitally for storage, printing, or later transmission. Initial tests include sickle cell disease, beta thalassemia, and COVID-19.