PHILADELPHIA (AP) — The U.S. Centers for Disease Control and Prevention asked hospitals nationwide Friday to review their laboratory procedures after a deadly error at a Philadelphia hospital.
St. Agnes Medical Center incorrectly interpreted a test used to measure blood clotting, leading dozens of patients to receive overdoses of a blood thinner. Two people died as a result, the city medical examiner ruled.
The lab error involved the prothrombin time (PT) test, which measures blood thickness. Physicians routinely use the test and the International Normalized Ratio to monitor the effect of warfarin — a widely prescribed anticoagulant better known by the brand name Coumadin — on the blood. The INR is a numeric value used to standardize PT results.
Employees at a St. Agnes lab failed to verify the sensitivity of a chemical reagent used in the PT test, leading them to use the wrong INR to calculate the result. The error, made between June 4 and July 25, led some physicians to prescribe a stronger dose of warfarin.