Coagulation Function Interpretation

Basic Interpretation of Normal Values

Normal PT/INR indicates normal functioning of the extrinsic and common coagulation pathways, including adequate levels of factors II, V, VII, X, and fibrinogen, as recommended by the American College of Cardiology 1, 3
Normal PT/INR and APTT suggest intact hemostatic function across all major coagulation pathways, according to the American College of Cardiology 1

Normal values rule out anticoagulant therapy effects, including vitamin K antagonist therapy, unfractionated heparin, and direct thrombin inhibitors, as stated by the American College of Cardiology 1, 2, 4
Normal values also rule out coagulation factor deficiencies, including factors II, V, VII, VIII, IX, X, XI, and fibrinogen, as indicated by the American College of Cardiology 1
Normal values suggest absence of pathological conditions, such as liver dysfunction, disseminated intravascular coagulation, and lupus anticoagulant, according to the American College of Cardiology 3, 4, 6, 7

Normal values indicate low risk of procedure-related bleeding from coagulation disorders in preoperative assessment, as recommended by the American College of Cardiology 3, 4
Normal values have poor predictive value for bleeding in patients with liver disease, trauma, or on direct oral anticoagulants, as stated by the American College of Cardiology 3
In patients on unfractionated heparin, normal APTT suggests subtherapeutic levels, according to the American College of Cardiology 2, 4
Normal values in trauma patients suggest absence of acute trauma coagulopathy, as indicated by the American College of Cardiology 1, 2