Using only an LED, plastic light filter and some wires, scientists at UCLA’s California NanoSystems Institute have modded a cellphone into a portable blood tester capable of detecting HIV, malaria and other illnesses.

UCLA researcher Dr. Aydogan Ozcan images thousands of blood cells instantly by placing them on an off-the-shelf camera sensor and lighting them with a coherent filtered-light source. That exposes distinctive qualities of the cells, which are then interpreted by Ozcan’s custom software. By analyzing the cell types present in a much larger sample, a more accurate diagnosis can be made in a matter of minutes. No more sending blood away to a lab and waiting days or weeks for the results.