Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (885 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
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.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Prothrombin Times; Time, Prothrombin; Times, Prothrombin; Russell's Viper Venom Time; Russell Viper Venom Time; Russells Viper Venom Time; Quick Test; Test, Quick.
Where it fits in the MeSH classification
- Broader topics
- Blood Coagulation Tests; Blood Physiological Phenomena
- See also
- Blood Coagulation
Related concepts
- Plasma
- Tissue Thromboplastin
- Fibrinogen
- Prothrombin
- Factor
- Factor Vii
- Coumarins
Research landscape
PubMed indexes 10,644 records tagged with the MeSH heading “Prothrombin Time” (counts retrieved 2026-10-31). 737 of them (6.9%) were published from 2020 onward, and the busiest period so far is through 1999 with 6,419 records.
Reviews account for 488 records (4.6%) and meta-analyses for 30. Randomized controlled trials number 370 (3.5%) as a share of all records on the topic.
Show the data
| Period | Records |
|---|---|
| through 1999 | 6,419 |
| 2000-2009 | 1,605 |
| 2010-2019 | 1,883 |
| 2020 onward | 737 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 488 | 4.6% |
| Meta-analyses | 30 | 0.3% |
| Randomized controlled trials | 370 | 3.5% |
Method: PubMed query "Prothrombin Time"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in anatomy and physiology
Anatomy describes how body structures are built and physiology describes how they normally work, so most findings here are descriptive or mechanistic rather than evidence about treatment. Much of what is known comes from dissection, imaging, tissue studies and experiments in animals, and measurements in healthy volunteers can differ from those in people with disease or at different ages. Normal ranges vary between individuals and populations. Check whether a result was measured in people or in another species, the age and health of the participants, and the method used.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
D-Dimer and Prothrombin Time Are the Significant Indicators of Severe COVID-19 and Poor Prognosis [1]
Abstract reading summary — source excerpts
- Opening excerpt
- ObjectiveTo investigate the value of coagulation indicators D-dimer (DD), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), and fibrinogen (Fg) in predicting the severity and prognosis of COVID-19.
- Closing excerpt
- DD and PT could be used as the significant indicators in predicting the mortality of COVID-19.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (236 words)
ObjectiveTo investigate the value of coagulation indicators D-dimer (DD), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), and fibrinogen (Fg) in predicting the severity and prognosis of COVID-19.MethodsA total of 115 patients with confirmed COVID-19, who were admitted to Tianyou Hospital of Wuhan University of Science and Technology between January 18, 2020, and March 5, 2020, were included. The dynamic changes of DD, PT, APTT, and Fg were tested, and the correlation with CT imaging, clinical classifications, and prognosis was studied.ResultsCoagulation disorder occurred at the early stage of COVID-19 infection, with 50 (43.5%) patients having DD increased and 74 (64.3%) patients having Fg increased. The levels of DD and Fg were correlated with clinical classification. Among 23 patients who deceased, 18 had DD increased at the first lab test, 22 had DD increased at the second and third lab tests, and 18 had prolonged PT at the third test. The results from ROC analyses for mortality risk showed that the AUCs of DD were 0.742, 0.818, and 0.851 in three times of test, respectively; PT was 0.643, 0.824, and 0.937. In addition, with the progression of the disease, the change of CT imaging was closely related to the increase of the DD value (P ConclusionsCoagulation dysfunction is more likely to occur in severe and critically ill patients. DD and PT could be used as the significant indicators in predicting the mortality of COVID-19.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 32596339 · DOI · PMC7301188
Point-of-care testing for emergency assessment of coagulation in patients treated with direct oral anticoagulants [2]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundPoint-of-care testing (POCT) of coagulation has been proven to be of great value in accelerating emergency treatment.
- Closing excerpt
- Retrospectively registered on 18 February 2015.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (245 words)
BackgroundPoint-of-care testing (POCT) of coagulation has been proven to be of great value in accelerating emergency treatment. Specific POCT for direct oral anticoagulants (DOAC) is not available, but the effects of DOAC on established POCT have been described. We aimed to determine the diagnostic accuracy of Hemochron® Signature coagulation POCT to qualitatively rule out relevant concentrations of apixaban, rivaroxaban, and dabigatran in real-life patients.MethodsWe enrolled 68 patients receiving apixaban, rivaroxaban, or dabigatran and obtained blood samples at six pre-specified time points. Coagulation testing was performed using prothrombin time/international normalized ratio (PT/INR), activated partial thromboplastin time (aPTT), and activated clotting time (ACT+ and ACT-low range) POCT cards. For comparison, laboratory-based assays of diluted thrombin time (Hemoclot) and anti-Xa activity were conducted. DOAC concentrations were determined by liquid chromatography-tandem mass spectrometry.ResultsFour hundred and three samples were collected. POCT results of PT/INR and ACT+ correlated with both rivaroxaban and dabigatran concentrations. Insufficient correlation was found for apixaban. Rivaroxaban concentrations at 95% specificity at PT/INR POCT ≤1.0 and ≤1.1 and ACT+ POCT ≤120 and ≤130 s. Dabigatran concentrations at 95% specificity at PT/INR POCT ≤1.1 and ≤1.2 and ACT+ POCT ≤100 s.ConclusionsHemochron® Signature POCT can be a fast and reliable alternative for guiding emergency treatment during rivaroxaban and dabigatran therapy. It allows the rapid identification of a relevant fraction of patients that can be treated immediately without the need to await the results of much slower laboratory-based coagulation tests.Trial registrationUnique identifier, NCT02371070 . Retrospectively registered on 18 February 2015.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 28196509 · DOI · PMC5309971
Clinical evaluation of whole blood prothrombin time (PT) and international normalized ratio (INR) using a Laser Speckle Rheology sensor [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Prothrombin time (PT) and the associated international normalized ratio (INR) are routinely tested to assess the risk of bleeding or thrombosis and to monitor response to anticoagulant therapy in patients.
- Closing excerpt
- These findings confirm the accuracy of our optical sensing approach for rapid PT/INR testing in whole blood and highlight the potential for use at the point-of-care or for patient self-testing.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (155 words)
Prothrombin time (PT) and the associated international normalized ratio (INR) are routinely tested to assess the risk of bleeding or thrombosis and to monitor response to anticoagulant therapy in patients. To measure PT/INR, conventional coagulation testing (CCT) is performed, which is time-consuming and requires the separation of cellular components from whole blood. Here, we report on a portable and battery-operated optical sensor that can rapidly quantify PT/INR within seconds by measuring alterations in the viscoelastic properties of a drop of whole blood following activation of coagulation with thromboplastin. In this study, PT/INR values were measured in 60 patients using the optical sensor and compared with the corresponding CCT values. Our results report a close correlation and high concordance between PT/INR measured using the two approaches. These findings confirm the accuracy of our optical sensing approach for rapid PT/INR testing in whole blood and highlight the potential for use at the point-of-care or for patient self-testing.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 28835607 · DOI · PMC5569083
International collaborative study for the calibration of a proposed World Health Organization International Standard for thromboplastin, human, recombinant: a report from the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC)-Scientific and Standardization Committee (SSC)/ISTH working group on prothrombin time/international normalized ratio standardization [4]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundThe availability of International Reference Preparations for thromboplastins, later on referred to as International Standards (ISs) for thromboplastins is essential for calibration of prothrombin time (PT) measurement systems and for the international normalized ratio (INR).
- Closing excerpt
- In this era of metrological traceability, a sustainable reference measurement system has been developed for PT/INR based on the harmonized manual tilt tube technique and a new IS.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (249 words)
BackgroundThe availability of International Reference Preparations for thromboplastins, later on referred to as International Standards (ISs) for thromboplastins is essential for calibration of prothrombin time (PT) measurement systems and for the international normalized ratio (INR). It is proposed to replace the current fifth IS for thromboplastin, human, recombinant (coded rTF/16) and the fifth IS for thromboplastin, rabbit, plain (coded RBT/16) by a single IS for defining a reference measurement system for PT/INR tests, in agreement with the concept of metrological traceability.ObjectivesThis study aimed to determine the international sensitivity index (ISI) for the proposed sixth IS for thromboplastin, human, recombinant (coded 24/114).MethodsAn international collaborative study was carried out for the assignment of the ISI to the proposed IS by calibration against the current fifth IS for thromboplastin, human, recombinant. PT measurements were performed by 8 trained operators in 4 laboratories (2 operators in each laboratory) using the harmonized manual tilt tube technique. The World Health Organization calibration procedure was followed.ResultsISI values from 8 operators varied from 1.04 to 1.12, and the mean ISI for the proposed IS coded 24/114 was 1.08 (between-operator coefficient of variation, 2.8%).ConclusionThe material coded 24/114 has been accepted by the World Health Organization as the sixth IS for thromboplastin, human, recombinant. Extensive prior training and external quality assessment surveys for the operators reduced the between-operator coefficient of variation. In this era of metrological traceability, a sustainable reference measurement system has been developed for PT/INR based on the harmonized manual tilt tube technique and a new IS.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42472241 · DOI · PMC13380524
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article How to interpret and pursue an abnormal prothrombin time, activated partial thromboplastin time, and bleeding time in adults [5]
- Research article Review article: the prothrombin time test as a measure of bleeding risk and prognosis in liver disease [6]
- Research article The international normalized ratio. A guide to understanding and correcting its problems [7]
- Research article Genetic associations for activated partial thromboplastin time and prothrombin time, their gene expression profiles, and risk of coronary artery disease [8]
- Research article ADULT CELIAC DISEASE WITH EMPHASIS UPON RESPONSE TO THE GLUTEN-FREE DIET [9]
- Research article Standardization of Prothrombin Time/International Normalized Ratio (PT/INR) [10]
References
- Long H, Nie L, Xiang X, Li H, Zhang X, Fu X, et al.. D-Dimer and Prothrombin Time Are the Significant Indicators of Severe COVID-19 and Poor Prognosis. . 2020. PMID 32596339 · DOI · PMC7301188
- Ebner M, Birschmann I, Peter A, Spencer C, Härtig F, Kuhn J, et al.. Point-of-care testing for emergency assessment of coagulation in patients treated with direct oral anticoagulants. . 2017. PMID 28196509 · DOI · PMC5309971
- Tripathi MM, Egawa S, Wirth AG, Tshikudi DM, Van Cott EM, Nadkarni SK. Clinical evaluation of whole blood prothrombin time (PT) and international normalized ratio (INR) using a Laser Speckle Rheology sensor. . 2017. PMID 28835607 · DOI · PMC5569083
- van der Helm MP, van Rijn CJJ, Baktawar SS, Abdoel CF, Kitchen S, Bryant M, et al.. International collaborative study for the calibration of a proposed World Health Organization International Standard for thromboplastin, human, recombinant: a report from the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC)-Scientific and Standardization Committee (SSC)/ISTH working group on prothrombin time/international normalized ratio standardization. . 2026. PMID 42472241 · DOI · PMC13380524
- Kamal AH, Tefferi A, Pruthi RK. How to interpret and pursue an abnormal prothrombin time, activated partial thromboplastin time, and bleeding time in adults. Mayo Clin Proc. 2007. PMID 17605969 · DOI
- Tripodi A, Caldwell SH, Hoffman M, Trotter JF, Sanyal AJ. Review article: the prothrombin time test as a measure of bleeding risk and prognosis in liver disease. Aliment Pharmacol Ther. 2007. PMID 17593061 · DOI
- Hirsh J, Poller L. The international normalized ratio. A guide to understanding and correcting its problems. Arch Intern Med. 1994. PMID 8297194 · DOI
- Tang W, Schwienbacher C, Lopez LM, Ben-Shlomo Y, Oudot-Mellakh T, Johnson AD, et al.. Genetic associations for activated partial thromboplastin time and prothrombin time, their gene expression profiles, and risk of coronary artery disease. Am J Hum Genet. 2012. PMID 22703881 · DOI · PMC3397273
- BENSON GD, KOWLESSAR OD, SLEISENGER MH. ADULT CELIAC DISEASE WITH EMPHASIS UPON RESPONSE TO THE GLUTEN-FREE DIET. Medicine (Baltimore). 1964. PMID 14115935 · DOI
- Dorgalaleh A, Favaloro EJ, Bahraini M, Rad F. Standardization of Prothrombin Time/International Normalized Ratio (PT/INR). Int J Lab Hematol. 2021. PMID 32979036 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-31.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.