['Recognition of trauma-induced coagulopathy by conventional coagulation testing (CCT) is limited by their slow results, incomplete characterization, and their poor predictive nature. Rapid thrombelastography (r-TEG) delivers a more comprehensive assessment of the coagulation system but has not been prospectively validated in trauma patients. The purpose of this pilot study was to evaluate the timeliness of r-TEG results, their correlation with CCTs, and the ability of r-TEG to predict early blood transfusion.', 'Over a 5-month period, 583 consecutive major trauma activations were prospectively entered into a database, of which 272 met entry criteria. r-TEG and CCTs (prothrombin time, international normalized ratio, partial thromboplastin time, and platelet count) were obtained on all patients. Graphical results for r-TEG were displayed "real time" in the trauma bay. Spearman\'s correlation and regression models were used to compare r-TEG and CCTs.', 'Early r-TEG values (activated clotting time [ACT], k-time, and r-value) were available within 5 minutes, late r-TEG values (maximal amplitude and α-angle) within 15 minutes, and CCTs within 48 minutes (p < 0.001). ACT, r-value, and k-time showed strong correlation with prothrombin time, international normalized ratio, and partial thromboplastin time (all r >0.70; p < 0.001), whereas maximal amplitude (r = -0.49) and α-angle (r = 0.40) correlated with platelet count (both p < 0.001). Linear regression demonstrated ACT predicted red blood cells (coef. 0.05; 95% confidence interval [CI], 0.04-0.06; p < 0.001), plasma (coef. 0.03; 95% CI, 0.02-0.04; p < 0.001), and platelet (coef. 0.06; 95% CI, 0.04-0.07; p < 0.001) transfusions within the first 2 hours of arrival. Controlling for all demographics and Emergency Department vitals, ACT >128 predicted massive transfusion (≥10 U) in the first 6 hours (odds ratio, 5.15; 95% CI, 1.36-19.49; p = 0.01). In addition, ACT <105 predicted patients who did not receive any transfusions in the first 24 hours (odds ratio, 2.80; CI, 1.02-7.07; p = 0.04).'] Does rapid thrombelastography deliver real-time results that predict transfusion within 1 hour of admission?