An immunoassay, a chief part of what Theranos’ Edison blood reader was meant to do, tests blood for reaction to antibodies. The presence of an antibody indicates that an immune system has been exposed to a microbial disease: “In laboratory speak, the word ‘assay’ is synonymous with ‘blood test’” (27). Chemiluminescence is the emitting of light during a chemical reaction: “When the reagents came into contact with the microscopic sandwiches, a chemical reaction occurred that emitted a light signal. An instrument inside the reader called a photomultiplier tube then translated the light signal into an electrical current" (27).

Despite her machines’ limitations, Theranos CEO Elizabeth Holmes promised that they would run 200 tests on a few drops of blood. Only some of these would be immunoassays; others would check cholesterol, Vitamin D levels, potassium, and the like. The company’s system never did work properly, however. 

Clinical Laboratory Improvement Amendments (CLIA) certificates are issued to labs that meet the standards of the Centers for Medicare and Medicaid Services (CMS), the federal agency responsible for managing Medicare and inspecting medical labs. Theranos lost its CLIA certificate in 2015 after CMS inspections found serious flaws in its laboratory practices.