Diagnostic performance of the ABC score in the PROPPR trial
Emily W Baird1, Daniel T Lammers1, Peter Abraham1
1Center for Injury Science, University of Alabama at Birmingham, Birmingham, AL, USA.
Introduction:
The Assessment of Blood Consumption (ABC) score is used to predict massive transfusions (MT). However, its diagnostic performance has not been widely examined, especially when used as an objective tool to enroll patients in multi-center clinical trials. The purpose of this study was to evaluate the performance of the ABC score in enrolling patients in the Pragmatic Randomized Optimal Platelet and Plasma Ratios (PROPPR) trial. We hypothesized the ABC score would have a similar diagnostic performance to predict the need for massive transfusion as previous studies.
Methods:
This is a retrospective analysis of the PROPPR trial. Patients were enrolled either on the basis of an ABC score ≥2, or by Physician Gestalt, when the ABC score was <2. We calculated the sensitivity, specificity, positive (PPV) and negative (NPV) predictive values and likelihood ratios of the ABC score (≥2) for predicting MT (>10 units of red blood cells/24 h or transfusion of >3 units of red blood cells within the first hour).
Results:
Of the 680 patients, 438 patients (64 %) had an ABC score of ≥2 and 242 (36 %) had an ABC score of <2. An ABC score of ≥2 had 66.8 % sensitivity and 37.0 % specificity for predicting the need for MT, with a PPV of 88.2 % and NPV of 13.1 %. Similarly, an ABC≥2 had 65.6 % sensitivity and 44.6 % specificity for predicting the need for >3 units RBCs in 1 hour, with a PPV of 89.5 % and NPV of 15.3 %.
Conclusion:
The ABC score had lower performance than previously reported for predicting MT, when applied to PROPPR trial patients. The performance for predicting the need for a 3-unit red blood cell transfusion (or more) in the first hour was slightly higher.
Level Of Evidence:
Level III, Prognostic.
