Print By Mayo Clinic Staff Request an appointment About Nov. 30, 2022 Print Show references Prothrombin time and international normalized ratio (PT/INR). Lab Tests Online. https://www.testing.com/tests/prothrombin-time-and-international-normalized-ratio-ptinr/. Accessed Nov. 3, 2022. Feldman M, et al., eds. Liver chemistry and function tests. In: Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis, Management. 11th ed. Elsevier; 2021.https://www.clinicalkey.com. Accessed Oct. 15, 2020. Gropper MA. Patient blood management: Coagulation. In: Miller's Anesthesia. 9th ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed Oct. 15, 2020. Mayo Clinic Laboratories. Prothrombin time (PT). https://www.mayocliniclabs.com/test-catalog/overview/602171#Clinical-and-Interpretive. Accessed Nov. 3, 2022. Excessive bleeding. Merck Manual Professional Version. https://www.merckmanuals.com/professional/hematology-and-oncology/hemostasis/excessive-bleeding. Accessed Nov. 3, 2022. Related News from Mayo Clinic Mayo Clinic Q & A: What to expect during a blood draw April 29, 2024, 12:46 p.m. CDT Products & Services A Book: Mayo Clinic Family Health Book A Book: Mayo Clinic on Digestive Health Newsletter: Mayo Clinic Health Letter — Digital Edition Show more products and services from Mayo Clinic Prothrombin time testAbout PRC-20157229 Patient Care & Health Information Tests & Procedures Prothrombin time test