Incidence of PRT/H Abs in healthy patients and patients undergoing CPB. (A) PRT/H antibody reactivity was measured by ELISA in healthy patients (Controls, n = 101) and patients after CPB (n = 500) at baseline, days 3 through 7, and day 30 after CPB. (B) Time course of seroconversion in all seropositive patients (n = 154; A_450nm >1.2). Each line represents the seroconversion profile of a patient after CPB.