Background: The use of international normalized ratio (INR) to diagnose vitamin K-dependent coagulation factor (VitK-CF) deficiency in trauma has limitations (inability to predict bleeding and long turnaround times). Thromboelastography (TEG) assesses the entire coagulation process. With TEG, reaction time (TEG-R) is used to assess global coagulation factor activity and takes less than 10 minutes. We assessed the ability of TEG-R to detect VitK-CF deficiency in trauma, compared to the INR.
Study design and methods: A total of 219 trauma patients with INR, TEG, and all VitK-CF measured at admission were included. Demographics and laboratory tests, drugs, blood transfusions, and severity scores were analyzed. Specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) of INR (≥1.3 and ≥1.5) and TEG-R (>8 min) to diagnose VitK-CF deficits (≤50%) were calculated. Secondary outcomes included time to INR and TEG results.
Results: Overall, TEG-R performed worse than INR. TEG-R had a sensitivity of 33% (95% CI, 16%-55%), specificity of 95% (95% CI, 91%-98%), PPV of 47% (95% CI, 23%-72%), and NPV of 92% (95% CI, 87%-95%). An INR of 1.5 or greater had a sensitivity of 67% (95% CI, 45%-84%), specificity of 98% (95% CI, 96%-99.7%), PPV of 84% (95% CI, 60%-97%), and NPV of 96% (95% CI, 92%-98%). An INR of 1.3 or greater also had better sensitivity, PPV, and NPV. For patients on warfarin, the times to INR results and TEG completion were 58 (±23) and 92 (±40) minutes (p=0.07), respectively. TEG-R was abnormal in only one patient on warfarin.
Conclusion: Our study suggests that TEG-R is not superior at identifying VitK-CF deficiency compared to INR in trauma.
© 2011 American Association of Blood Banks.