Purpose:Exsanguination is the most common leading cause of death in trauma patients.The massive transfusion (MT) protocol may influence therapeutic strategies and help provide blood components in timely manner.The assessment of blood consumption (ABC) score is a popular MT protocol but has low predictability.The lactate level is a good parameter to reflect poor tissue perfusion or shock states that can guide the management.This study aimed to modify the ABC scoring system by adding the lactate level for better prediction of MT.Methods:The data were retrospectively collected from 165 trauma patients following the trauma activated criteria at Songklanagarind Hospital from January 2014 to December 2014.The ABC scoring system was applied in all patients.The patients who had an ABC score ≥2 as the cut point for MT were defined as the ABC group.All patients who had a score ≥2 with a lactate level ＞4 mmol/dL were defined as the ABC plus lactate level (ABC + L) group.The prediction for the requirement of massive blood transfusion was compared between the ABC and ABC + L groups.The ability of ABC and ABC + L groups to predict MT was estimated by the area under the receiver operating characteristic curve (AUROC).Results:Among 165 patients,15 patients (9％) required massive blood transfusion.There were no significant differences in age,gender,mechanism of injury or initial vital signs between the MT group and the non-MT group.The group that required MT had a higher Injury Severity Score and mortality.The sensitivity and specificity of the ABC scoring system in our institution were low (81％,34％,AUC 0.573).The sensitivity and specificity were significantly better in the ABC + L group (92％,42％,AUC =0.745).Conclusion:The ABC scoring system plus lactate increased the sensitivity and specificity compared with the ABC scoring system alone.