Comparing the prothrombin time INR versus the APTT to evaluate the coagulopathy of acute trauma

Thromb Res. 2007;120(1):29-37. doi: 10.1016/j.thromres.2006.07.002. Epub 2006 Aug 2.


Introduction: In trauma patients, PT/INR or aPTT cutoffs of > or =1.5x normal are often used as triggers for the transfusion of plasma.

Material and methods: To evaluate the ability of the PT/INR or aPTT to predict low coagulation factor levels, these tests were compared to coagulation factor levels in samples with artificially prepared single and multiple factor deficiencies, 9 heparin-contaminated samples, 10 lupus inhibitor-containing samples, 21 samples with elevated factor VIII levels, and 35 samples from acute trauma patients.

Results and conclusions: The PT/INR and aPTT showed comparable sensitivity for single or multiple factor deficiencies in artificially deficient plasmas, but the PT/INR was more sensitive than the aPTT to low coagulation factor levels in actual trauma patients (sensitivity 84% versus 50%). The aPTT can show false positives with lupus anticoagulants and heparin contamination and false negatives in samples with elevated factor VIII. Thus, in the acute trauma setting, the PT/INR cutoff is a more reliable indicator of reduced coagulation factor levels.

Publication types

  • Clinical Trial
  • Comparative Study

MeSH terms

  • Acute Disease
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Blood Coagulation Factors / metabolism*
  • Child
  • Female
  • Humans
  • International Normalized Ratio*
  • Male
  • Middle Aged
  • Partial Thromboplastin Time*
  • Predictive Value of Tests
  • Prothrombin Time*
  • Sensitivity and Specificity
  • Wounds and Injuries / blood*


  • Blood Coagulation Factors