Helen Free, Diabetes Testing
The foundation of self-care for diabetics is home glucose monitoring, invented by Helen Free and her husband, Alfred, when they were both chemists for Miles Laboratory, now Bayer. It’s critical for diabetics to have a reliable way to gauge if their blood sugar level is too high or low so they know whether to take extra insulin or have a snack. But laymen didn’t have specialized knowledge to conduct the laboratory tests needed to obtain the information.
The Frees changed all that by developing the Clinitest. Patients put urine in a test tube, dropped in a tablet, and waited for the color to change; the different shades corresponded to different glucose levels. In 1954 they developed dip-and-read “Clinistix,” which became a key tool for diabetes management. The same idea is used today with test strips that provide exquisitely precise measurements from tiny drops of blood.
Over the years Free and her husband became known as the foremost experts in urinalysis, writing the book that remains the standard text in the field. It helped, she said, that they had six children. “There was always plenty of urine to test,” she said later.
Free later became Director of Specialty Test Systems at Bayer and served as president of the American Chemical Society in 1993.
