PT

Alternative names:

pro-time; prothrombin time

Normal values:

The normal range is 11 to 12.5 seconds ("normal" varies somewhat in different labs).

For a person on full anticoagulant therapy the PT should be 1.5 to 2 times the laboratory "control" value.

What abnormal results mean:

Increased PT times may indicate:

• bile duct obstruction
• cirrhosis
• disseminated intravascular coagulation
• hepatitis
• malabsorption (inadequate absorption of nutrients from the intestinal tract)
• vitamin K deficiency
• Coumadin (warfarin) therapy

Additional conditions under which the test may be performed:

• acquired platelet function defect
• congenital platelet function defects
• congenital protein C or S deficiency
• deep intracerebral hemorrhage
• DIC (Disseminated intravascular coagulation)
• factor II deficiency
• factor V deficiency
• factor VII deficiency
• factor X deficiency
• hemolytic-uremic syndrome (HUS)
• hemophilia A
• hemophilia B
• hemorrhagic stroke
• hepatic Encephalopathy
• hepatorenal syndrome
• hypertensive intracerebral hemorrhage
• idiopathic thrombocytopenic purpura (ITP)
• intracerebral hemorrhage
• lobar intracerebral hemorrhage
• placenta abruptio
• transient ischemic attack (TIA)
• Wilson's disease