Regina Kapeller-Adler, born Regina Kapeller, (28 June 1900 – 31 July 1991) was an Austrian biochemist who, in 1934, devised an innovative test for early pregnancy based on the detection of histidine in urine. As a Jew, she was forced to leave Austria following the country's annexation into Nazi Germany in the Anschluss and went to work with the noted geneticist Francis Crew at the Institute of Animal Genetics at the University of Edinburgh.