{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,19]],"date-time":"2026-10-19T16:36:29Z","timestamp":1792427789012,"version":"4.5.0"},"reference-count":54,"publisher":"Walter de Gruyter GmbH","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2016,1,1]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Prothrombin time (PT) and activated partial thromboplastin time (APTT) are the most widely used tests to investigate coagulation abnormalities. Varied result reporting have been introduced over the years for the two tests, thus making their interpretation rather confusing in different clinical settings. PT results have been reported as clotting time, percentage activity, PT-ratio (patient-to-normal clotting time) and as international normalized ratio (INR). The INR scale has been devised to harmonize results stemming from different thromboplastins from patients on treatment with vitamin K antagonists. Therefore, there are some theoretical and evidence-based considerations that make the INR formally invalid when the test is used to analyze patients in other clinical settings. Unfortunately, this limitation has been frequently overlooked, and the INR has been (and is currently) used as a universal system of results harmonization. The APTT has been historically reported as clotting time or as ratio (patient-to-normal clotting time). In this opinion paper we review the current state-of-the-art for result reporting and attempt to give practical guidance on how PT and APTT should be reported in different clinical conditions for which the tests are requested.<\/jats:p>","DOI":"10.1515\/cclm-2015-0657","type":"journal-article","created":{"date-parts":[[2015,8,6]],"date-time":"2015-08-06T13:03:03Z","timestamp":1438866183000},"source":"Crossref","is-referenced-by-count":29,"title":["How to report results of prothrombin and activated partial thromboplastin times"],"prefix":"10.1515","volume":"54","author":[{"given":"Armando","family":"Tripodi","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Giuseppe","family":"Lippi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mario","family":"Plebani","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"374","reference":[{"key":"ref661","doi-asserted-by":"crossref","first-page":"604","DOI":"10.1055\/s-0028-1104539","article-title":"Activated partial thromboplastin time : new tricks for an old dogma","volume":"11","author":"Lippi","year":"2008","journal-title":"Semin Thromb Hemost"},{"key":"ref621","article-title":"Scientific Subcommittee on Disseminated Intravascular Coagulation of the International Society on and Towards definition clinical and laboratory criteria and a scoring system for disseminated intravascular coagulation","volume":"30","author":"Taylor","year":"2001","journal-title":"DIC Thrombosis Haemostasis"},{"key":"ref401","first-page":"637","article-title":"KM Effect of anti - hemophilic factor on one stage clotting tests : a presumptive test for hemophilia and a simple one - stage anti - hemophilic assay procedure","author":"Langdell","year":"1953","journal-title":"J Lab Clin Med"},{"key":"ref241","article-title":"Scientific Subcommittee on Disseminated Intravascular Coagulation of the International Society on and Towards definition clinical and laboratory criteria and a scoring system for disseminated intravascular coagulation","volume":"30","author":"Taylor","year":"2001","journal-title":"DIC Thrombosis Haemostasis"},{"key":"ref171","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1053\/gast.2003.50016","article-title":"United Network for Organ Sharing Liver Disease Severity Score Committee Model for end - stage liver disease and allocation of donor liver","volume":"124","author":"Wiesner","year":"2003","journal-title":"Gastroenterology"},{"key":"ref381","doi-asserted-by":"crossref","first-page":"585","DOI":"10.1055\/s-0028-1104537","article-title":"The history of phenotypic testing in thrombosis and hemostasis","author":"Tripodi","year":"2008","journal-title":"Semin Thromb Hemost"},{"key":"ref691","first-page":"73","article-title":"der Poller The monitoring of heparin the ISTH collaborative study","author":"Van","year":"1995"},{"key":"ref131","doi-asserted-by":"crossref","first-page":"2137","DOI":"10.1515\/cclm-2012-0327","article-title":"Position paper on laboratory testing for patients taking new oral anticoagulants Consensus document of","author":"Tripodi","year":"2012","journal-title":"Clin Chem Lab Med"},{"key":"ref511","doi-asserted-by":"crossref","first-page":"2137","DOI":"10.1515\/cclm-2012-0327","article-title":"Position paper on laboratory testing for patients taking new oral anticoagulants Consensus document of","author":"Tripodi","year":"2012","journal-title":"Clin Chem Lab Med"},{"key":"ref111","doi-asserted-by":"crossref","DOI":"10.1111\/j.1538-7836.2006.01910.x","article-title":"den International collaborative study for the calibration of a proposed international standard for thromboplastin rabbit plain","author":"Chantarangkul","year":"2006","journal-title":"AM J Thromb Haemost"},{"key":"ref331","first-page":"141","article-title":"DA Parenteral anticoagulants antithrombotic therapy and prevention of thrombosis th ed American College of Chest Physicians Evidence - 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analytical external quality assessment programme","author":"Thue","journal-title":"Clin Chem Lab Med"},{"key":"ref11","first-page":"73","article-title":"The prothrombin in hemophilia and in obstructive jaundice","volume":"109","author":"Quick","year":"1935","journal-title":"J Biol Chem"},{"key":"ref641","first-page":"874","article-title":"van der Poll short contemporary history of disseminated intravascular coagulation","author":"Levi","year":"2014","journal-title":"Semin Thromb Hemost"},{"key":"ref51","first-page":"565","article-title":"Poller Standardization of anticoagulant treatment the Manchester Regional Thromboplastin Scheme ii","year":"1964","journal-title":"Med"},{"key":"ref291","first-page":"287","article-title":"prospective study of the value of monitoring heparin treatment with the activated partial thromboplastin time","author":"Basu","year":"1972","journal-title":"Engl J Med"},{"key":"ref711","first-page":"141","article-title":"DA Parenteral anticoagulants antithrombotic therapy and prevention of thrombosis th ed American College of Chest Physicians Evidence - 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