Misinterpretation of Prothrombin Time in Warfarin Anticoagulation

Letters and Corrections1 September 1981Misinterpretation of Prothrombin Time in Warfarin AnticoagulationRICHARD N. PALMER, M.D., CRAIG M. KESSLER, M.D., HARVEY R. GRALNICK, M.D.RICHARD N. PALMER, M.D.Search for more papers by this author, CRAIG M. KESSLER, M.D.Search for more papers by this author, HARVEY R. GRALNICK, M.D.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-95-3-393_2 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptTo the editor: The prothrombin time is the commonest test used to monitor oral anticoagulant therapy. In examining the prothrombin times of patients on oral anticoagulants and normal subjects, we have found a time-dependent shortening of the test when whole blood is kept in borosilicate (or glass) or in commercial siliconized borosilicate tubes, both at 4 °C, and to a lesser degree at 23 °C. This shortening of the prothrombin time is minimal when polypropylene tubes are used.The prothrombin times for blood collected in borosilicate tubes are given in Figure 1. Almost identical results were found with commercial siliconized...References1. RADCLIFFEBAGDASARIANCOLMANNEMERSON RARY. Activation of bovine factor VII by Hageman factor fragments. Blood. 1977;50:611-7. CrossrefMedlineGoogle Scholar2. KISIELFUJIKAWADAVIE WKE. Activation of bovine factor VII (proconvertin) by factor XIIa (activated Hageman factor). Biochem. 1977;16:4189-94. CrossrefMedlineGoogle Scholar3. LAAKEOSTERUD KB. Activation of purified plasma factor VII by human plasmin, plasma kallikrein and activated components of the human intrinsic blood coagulation system. Thromb Res. 1974;5:759-72. CrossrefMedlineGoogle Scholar4. GJONNAESS H. Cold promoted activation of factor VII. Thromb Diath Haemorrh. 1972;28:155-68. MedlineGoogle Scholar5. RATNOFFROSENBLUM OJ. Role of Hageman factor in the initiation of clotting by glass. Am J Med. 1958;25:160-8. CrossrefMedlineGoogle Scholar6. BYNUMWILSON LJ. Low-dose heparin therapy in the long-term management of venous thromboembolism. Am J Med. 1979;67:553-6. CrossrefMedlineGoogle Scholar7. HULLDELMOREGENTON RTE. Warfarin sodium versus low-dose heparin in the long-term treatment of venous thrombosis. N Engl J Med. 1979;301:855-8. CrossrefMedlineGoogle Scholar This content is PDF only. To continue reading please click on the PDF icon. Author, Article, and Disclosure InformationAffiliations: National Institutes of Health Bethesda, MD 20205 PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetails Metrics Cited byThe use of Vacutainer tubes for collection and storage of blood for coagulation testingProthrombin TimeBERNARD A. COOPER, M.D., MAVIS LEZNOFF, R.T.Variables Affecting Measurement of Prothrombin TimeSAMUEL CHARACHE, M.D., M. EULALIA HARBAUGH, M.T.Subacute Wernicke's encephalopathy due to gastric syphilisDie Krankheiten des Magens 1 September 1981Volume 95, Issue 3Page: 393-394KeywordsAnticoagulant therapyAnticoagulantsBloodHematologic testsProthrombin time Issue Published: 1 September 1981 PDF downloadLoading ...