In the rural parts of Uganda, lab technicians spend hours each day on thankless and seemingly unceasing work. The most common tests they run are for malaria. A technician smears a blood sample on a slide, treats it with dye, and then slowly scans it for cells that contain malaria parasites. She then uses a handheld clicker to record how many parasites she sees.
A typical test might take from 30 minutes to an hour. A health center might see dozens of patients in a day. When Manu Prakash visited on a recent trip, “There were places where the technicians couldn’t stop to talk to me, because they were busy working, which could last for eight to 10 hours per day,” he says.
An Indian-born biophysicist who works at Stanford University, Prakash is best known for creating the Foldscope—a $1 pocket microscope that magnifies objects by more than 2,000 times and can be folded from a single sheet of paper embedded with microoptics. But on this trip, while field-testing the Foldscope, Prakash realized that being cheap wasn’t enough. His devices also needed to be fast.
Rapid diagnostic tests can quickly check whether someone has malaria, but they don’t count the number of parasites. That figure is important: It reveals the severity of an infection and informs treatment choices. To count parasites, you need trained technicians and good microscopes. “There’s incredible talent, but it’s limited by their tools,” Prakash says. “I would meet health-care workers who would save their salary for a year to buy a fancier microscope.”