• (prothrombin time) A blood clotting measurement that evaluates the extrinsic pathway of coagulation.
  CDISC Terminology
  Clinical Data Interchange Standards Consortium (CDISC), 2021
• (prothrombin time) A measurement of the clotting time of plasma recalcified in the presence of excess tissue thromboplastin; it is a measure of the extrinsic pathway of coagulation. It is used to determine the clotting tendency of blood, in the measure of warfarin dosage, liver damage and vitamin K status. Factors measured are fibrinogen, prothrombin, and factors V, VII, and X.
  NCI
  U.S. National Cancer Institute, 2021
• (prothrombin time) Clotting time of PLASMA recalcified in the presence of excess TISSUE THROMBOPLASTIN. Factors measured are FIBRINOGEN; PROTHROMBIN; FACTOR V; FACTOR VII; and FACTOR X. It is used for monitoring anticoagulant therapy with COUMARINS.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• A basic understanding of the coagulation pathway is required to interpret prothrombin time result (see the image below). The prothrombin time is a measure of the integrity of the extrinsic and final common pathways of the coagulation cascade.
  Medscape
  WebMD, 2025