Indicator Explainer
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.
This page explains what the indicator is and how results are interpreted in general terms. Reference ranges depend on the laboratory, the method, and your own situation — no single “normal value” applies to everyone. This page is health information, not a diagnosis. For symptoms, treatment, or urgent concerns, contact a healthcare professional.
When it is tested
Source: National Cancer Institute, NCI Thesaurus 26.09d, C62656. NCI definition, reproduced without modification under CC BY 4.0. Source identity and definition checked automatically on 2026-10-19. No individual clinical interpretation or human reviewer is asserted.
Reading results
Reference intervals and interpretation depend on the laboratory, specimen, method and clinical context. This source definition is educational information; it does not establish a diagnosis, product approval or suitability for an individual.
Also Known As
Related Tests
Tests that measure or involve this indicator.
References
- NCI Thesaurus 26.09d — Prothrombin Time (C62656)
- Source: National Cancer Institute, NCI Thesaurus 26.09d, C62656. NCI definition, reproduced without modification under CC BY 4.0.
- Unlocking Prognostic Potential: Serum Uric Acid and Prothrombin Time as Predictors of HCC Recurrence. — Clin Lab, 2026-10-01 (PMID 42847944; literature)
- Conventional Prothrombin Time and Activated Partial Thromboplastin Time Mask Citrate-Induced Divalent Cation Depletion During Frozen Plasma Transfusion. — Anesth Analg, 2026-09-30 (PMID 42805188; literature)
- Diagnosis-Day Prothrombin Time and Transaminase as Exploratory Risk-Stratification Indicators for Severe Neonatal Outcomes in Acute Fatty Liver of Pregnancy. — Gynecol Obstet Invest, 2026-10-12 (PMID 42862769; literature)
- The Quick and Owren prothrombin time assays: characteristics and performance in clinical routine. — J Thromb Haemost, 2026-10-26 (PMID 42933656; literature)
- Re: Prognostic significance of the prothrombin time-international normalized ratio to albumin ratio in cancer patients with complication of sepsis: a retrospectively cohort study. — Shock, 2026-10-22 (PMID 42911410; literature)