For a growing number of medical startups, the holy grail is to develop technology that can diagnose hundreds of diseases with a single drop of blood.
Many people are squeamish about getting their blood drawn by traditional methods, such as inserting a long needle into a vein. And in developing countries, health clinics are eager for "lab on a chip" diagnostics that can be done without piercing a vein.
But researchers are finding myriad challenges with relying on a single blood drop. In a recent experiment, scientists at Rice 360° Institute for Global Health took seven drops of blood from 10 individuals. They tested each blood drop for basic health measures, such as hemoglobin and platelet counts, and found a wide range of results between drops that came from the same person.
"These data suggest caution when using measurements from a single drop of fingerprick blood," researchers Meaghan M. Bond and Rebecca R. Richards-Kortum concluded in The American Journal of Clinical Pathology.
Bond and Richards-Kortum told the New York Times that in order to achieve results as accurate as conventional methods—the venous blood draw—they had to average six to nine drops of blood from each individual.
In recent months, Theranos, a company that hoped to revolutionize the blood-testing industry, has come under fire from federal regulators. Theranos's CEO Elizabeth Holmes once promised to detect dozens of medical conditions, from high cholesterol to cancer, based on a few drops of blood.
San Diego-based Genalyte is also working on a diagnostics system to produce test results from a single blood drop. But unlike Theranos, Genalyte has generated a number of peer-reviewed studies to validate its approach. The company is focusing initially on autoimmune diseases, such as lupus and rheumatoid arthritis.