Prothrombin with INR and Partial Thromboplastin Times (PTT)

Doctors usually require this test before surgeries to ensure someone can coagulate properly during an operation.

Prothrombin with INR and Partial Thromboplastin Times - PT/INR: A screening test for abnormalities of coagulation factors that are involved in the extrinsic pathway. Also used to monitor the effects of Warfarin therapy and to study patients with hereditary and acquired clotting disorders.

The PT and PTT Blood Tests are helpful in the diagnosis of excessive, unexplained bleeding in patients who are not taking blood-thinning medications. These bleeding disorders include nosebleeds, bruising, heavy menstrual periods, blood in the stool and/or urine, and bleeding gums. The tests are sometimes ordered for patients before surgery to ensure normal clotting ability.

A “prolonged” result means a blood clot takes longer than normal to form. There are a variety of causes for this, including coagulation/clotting factor deficiency/dysfunction, vitamin K deficiency, liver disease, inhibition by specific antibodies, and others. The general interpretation of PT & PTT Blood Test results can be summarized as follows:

• PT prolonged, PTT prolonged: Dysfunctional or insufficient coagulation factor I, II, V, or X; acute disseminated intravascular coagulation (DIC) (abnormal activation of coagulation factors); severe liver disease.

• PT prolonged, PTT normal: Dysfunctional or insufficient coagulation factor VII, chronic low-grade DIC, insufficient vitamin K, liver disease, warfarin (anticoagulant) therapy.

• PT normal, PTT prolonged: Dysfunctional or insufficient coagulation factor VIII, IX, or XI; severe von Willebrand disease (hereditary bleeding disorder); the presence of lupus anticoagulant.

• PT normal, PTT normal or slightly prolonged: Normal clotting ability, mild deficiencies in other coagulation factors, a mild form of von Willebrand disease