Validation of the PLASMIC score at a University Medical Center

Background The PLASMIC score was recently described as a convenient tool for predicting ADAMTS13 activity ≤10% in patients with possible thrombotic thrombocytopenic purpura (TTP), while awaiting the results of this send-out test. The purpose of this study was to validate the PLASMIC score at our University Medical Center. Methods Apheresis records were reviewed from 2008 to 2017 to identify patients who received plasma exchange (PLEX) for suspected TTP. The ADAMTS13 activity and PLASMIC scoring criteria were recorded, and the PLASMIC score was calculated. Results Of the 41 patients identified, 20 met inclusion criteria, of which 7 patients had ADAMTS13 activity ≤10%. Intermediate and high PLASMIC scores had 100% sensitivity, 46.2% specificity, 50% positive predictive value (PPV), and 100% negative predictive value (NPV). Conclusion These results are consistent with the original validation study of the PLASMIC score, supporting the efficacy of the PLASMIC score and validating its use at our institution.