What is Prothrombin Time?
Prothrombin time is the time it takes for plasma to clot. Plasma is the liquid portion of blood. Doctors typically order the prothrombin time test to gauge how well clotting medications are working or to verify there is a clotting problem as part of the diagnostic process. Liver disease, hemophilia and other clotting disorders may be associated with abnormal prothrombin times.

Normal Value Range

  • Negative Pregnancy Adult: 12.7 to 15.4 seconds
  • Pregnancy Trimester One: 9.7 to 13.5 seconds
  • Pregnancy Trimester Two: 9.5 to 13.4 seconds
  • Pregnancy Trimester Three: 9.6 to 12.9 seconds

Impaired prothrombin time can cause excessive bleeding or bruising. If the patient is suffering from vitamin K deficiency, prothrombin and other clotting elements in blood cannot be produced in adequate amounts.

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