Adverse analytical finding due to red blood cells transfusion: A rare case involving the diuretic dorzolamide

Early November 2020 an Olympic gold medal winner returned during an out-competition control an adverse analytical finding for dorzolamide, a diuretic mostly used to treat glaucoma. Estimated urine concentrations were 2.2 and 1.6 ng/ml in the A and B specimens, respectively. As the athlete denied any use of dorzolamide, a complex forensic investigation was suggested. It revealed that the athlete was severely injured during a car crash 6 months before where he received 2× 500 ml of red blood cells transfusion. One of the blood donors declared using dorzolamide. A plasma aliquot, stored for legal purposes, was tested by LC-MS/MS several months later and contained 4.3 ng/ml of dorzolamide. Given the very long half-life of the drug, up to 150 days and its reported incorporation into erythrocyte, it was accepted by the French antidoping administration (AFLD) that the source of contamination was this blood transfusion and that the antidoping rule violation was unintended.