In the 1950s the US chemist Helen Murray Free, who has died aged 98, was responsible for developing glucose dipsticks. Their use led to much simpler medical screening methods that are still widely used today for pregnancy tests, the diagnosis and monitoring of diabetes, and to detect and monitor a range of kidney, liver and metabolic disorders and other medical conditions.
Before then, without central testing laboratories, if a patient needed to be tested for diabetes the analysis work was done in the doctor’s office: mixing urine with chemicals such as copper sulphate, heating it over a Bunsen burner and looking for a red-orange precipitate indicating sugar. It was time-consuming, restricting the number of tests a doctor carried out, and inconclusive, as it did not differentiate between glucose (indicating diabetes) and other sugars.
