Diagnostics for All, a nonprofit in Cambridge, Massachusetts, is making a test for liver damage that could cost just pennies. It consists, remarkably, of a stamp-size square of paper with wells that change color when a drop of blood is applied.
The test could provide an enormous benefit in poor countries, where liver damage is widespread as a side effect of drugs administered to HIV and tuberculosis patients. (As many as one-fourth of people taking antiretroviral drugs in the poor world develop liver problems—five times the rate elsewhere.) The liver function tests administered regularly in the developed world require tubes of blood, lab equipment, and electricity. The paper chip from Diagnostics for All needs none of that.