Captopril therapy and pseudoketonuria: A clinical assessment

Studies have suggested that the angiotensin converting enzyme inhibitor captopril may cause false positive urine tests for acetone. The phenomenon of misinterpretation of urinary ketone‐test strip results in patients taking captopril was investigated in 25 diabetic and 25 non‐diabetic patients over a period of 28 days. Four of the 50 patients had a weak positive test with Ketostix and one of these also showed a weak positive Ketur test. Although the incidence of false positive results was relatively low, it should be borne in mind when advising diabetics on self testing for ketones.