Prothrombin Time (PT)

CMS National Coverage Determination | ncd_id=80 | manual_section=190.17 | coverage_level_code=2 | national_coverage_type=True | under_review=True | lab_ncd=True

Indications A PT may be used to assess patients taking warfarin. The prothrombin time is generally not useful in monitoring patients receiving heparin who are not taking warfarin. A PT may be used to assess patients with signs or symptoms of abnormal bleeding or thrombosis. For example: swollen extremity with or without prior trauma; unexplained bruising; abnormal bleeding, hemorrhage or hematoma; petechiae or other signs of thrombocytopenia that could be due to disseminated intravascular coagulation. A PT may be useful in evaluating patients who have a history of a condition known to be associated with the risk of bleeding or thrombosis that is related to the extrinsic coagulation pathway. Such abnormalities may be genetic or acquired. For example: dysfibrinogenemia; afibrinogenemia (complete); acute or chronic liver dysfunction or failure, including Wilson's disease and Hemochromatosis; disseminated intravascular coagulation (DIC); congenital and acquired deficiencies of factors II, V, VII, X; vitamin K deficiency; lupus erythematosus; hypercoagulable state; paraproteinemia; lymphoma; amyloidosis; acute and chronic leukemias; plasma cell dyscrasia; HIV infection; malignant neoplasms; hemorrhagic fever; salicylate poisoning; obstructive jaundice; intestinal fistula; malabsorption syndrome; colitis; chronic diarrhea; presence of peripheral venous or arterial thrombosis or pulmonary emboli or myocardial infarction; patients with bleeding or clotting tendencies; organ transplantation; presence of circulating coagulation inhibitors. A PT may be used to assess the risk of hemorrhage or thrombosis in patients who are going to have a medical intervention known to be associated with increased risk of bleeding or thrombosis. For example: evaluation prior to invasive procedures or operations of patients with personal history of bleeding or a condition associated with coagulopathy prior to the use of thrombolytic medication. Limitations When an ESRD patient is tested for PT, testing more frequently than weekly requires documentation of medical necessity, e.g., other than chronic renal failure or renal failure, unspecified. The need to repeat this test is determined by changes in the underlying medical condition and/or the dosing of warfarin. In a patient on stable warfarin therapy, it is ordinarily not necessary to repeat testing more than every two to three weeks. When testing is performed to evaluate a patient with signs or symptoms of abnormal bleeding or thrombosis and the initial test result is normal, it is ordinarily not necessary to repeat testing unless there is a change in the patient's medical status. Since the INR is a calculation, it will not be paid in addition to the PT when expressed in seconds, and is considered part of the conventional PT test. Testing prior to any medical intervention associated with a risk of bleeding and thrombosis (other than thrombolytic therapy) will generally be considered medically necessary only where there are signs or symptoms of a bleeding or thrombotic abnormality or a personal history of bleeding, thrombosis or a condition associated with a coagulopathy. Hospital/clinic-specific policies, protocols, etc., in and of themselves, cannot alone justify coverage. Note: Scroll down for links to the quarterly Covered Code Lists (including narrative).

Item/Service Description: Basic plasma coagulation function is readily assessed with a few simple laboratory tests: the partial thromboplastin time (PTT), PT, thrombin time (TT), or a quantitative fibrinogen determination. The PT test is one in-vitro laboratory test used to assess coagulation. While the PTT assesses the intrinsic limb of the coagulation system, the PT assesses the extrinsic or tissue factor dependent pathway. Both tests also evaluate the common coagulation pathway involving all the reactions that occur after the activation of factor X. Extrinsic pathway factors are produced in the liver and their production is dependent on adequate vitamin K activity. Deficiencies of factors may be related to decreased production or increased consumption of coagulation factors. The PT/INR is most commonly used to measure the effect of warfarin and regulate its dosing. Warfarin blocks the effect of vitamin K on hepatic production of extrinsic pathway factors. A PT is expressed in seconds and/or as an international normalized ratio (INR). The INR is the PT ratio that would result if the WHO reference thromboplastin had been used in performing the test. Current medical information does not clarify the role of laboratory PT testing in patients who are self monitoring. Therefore, the indications for testing apply regardless of whether or not the patient is also PT self-testing. Cross Reference: Also see the Medicare Claims Processing Manual , Chapter 120, Clinical Laboratory Services Based on Negotiated Rulemaking. Other Text: Covered Code Lists (including narrative) January 2026 (PDF) ( ICD-10 ) October 2025 (PDF) ( ICD-10 ) January 2025 (PDF) ( ICD-10 ) October 2024 (PDF) ( ICD-10 ) July 2024 (PDF) ( ICD-10 ) April 2024 (PDF) ( ICD-10 ) January 2024 (PDF) ( ICD-10 ) October 2023 (PDF) ( ICD-10 ) July 2023 (PDF) ( ICD-10 ) April 2023 (PDF) ( ICD-10 ) January 2023 (PDF) ( ICD-10 ) October 2022 (PDF) ( ICD-10 ) July 2022 (PDF) ( ICD-10 ) April 2022 (PDF) ( ICD-10 ) January 2022 (PDF) ( ICD-10 ) October 2021 (PDF) ( ICD-10 ) July 2021 (PDF) ( ICD-10 ) April 2021 (PDF) ( ICD-10 ) January 2021 (PDF) ( ICD-10 ) October 2020 (PDF) ( ICD-10 ) July 2020 (PDF) ( ICD-10 ) April 2020 (PDF) ( ICD-10 ) January 2020 (PDF) ( ICD-10 ) October 2019 (PDF) ( ICD-10 ) July 2019 (PDF) ( ICD-10 ) April 2019 (PDF) ( ICD-10 ) January 2019 (PDF) ( ICD-10 ) October 2018 (PDF) ( ICD-10 ) July 2018 (PDF) ( ICD-10 ) April 2018 (PDF) ( ICD-10 ) January 2018 ( ICD-10 ) October 2017 ( ICD-10 ) July 2017 ( ICD-10 ) April 2017 ( ICD-10 ) January 2017 ( ICD-10 ) October 2016 ( ICD-10 ) January 2016 ( ICD-10 ) October 2015 ( ICD-10 , ICD-9 ) October 2014 ( ICD-10 , ICD-9 ) Changes to Lab NCD Edit Software January 2026 October 2025 January 2025 October 2024 July 2024 January 2024 October 2023 April 2023 January 2023 October 2022 April 2022 January 2022 October 2021 July 2021 October 2020 April 2020 January 2020 October 2019 July 2019 January 2019 October 2018 April 2018 January 2018 July 2017 April 2017 January 2017 January 2016 October 2014 Revision History: 07/2004 - Published NCD in the NCD Manual without change to narrative contained in PM AB-02-110. Coding guidance now published in Medicare Lab NCD Manual. Effective and Implementation dates NA. ( TN 17 ) (CR 2130) 07/2002 - Implemented NCD. Effective date 11/25/02. Implementation date 1/01/03. ( TN AB-02-110 ) (CR 2130) Benefit Categories: 18 - Diagnostic Laboratory Tests Transmittal: transmittal_number=17 | transmittal_issue_date=2004-07-02 | change_request_number=2130