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Home Prothrombin Time Testing (INR Monitoring)

Policy Number: MP-078

Latest Review Date:  November 2022

Category:  Durable Medical Equipment (DME)


Home prothrombin time monitoring may be considered medically necessary in individuals who require continuous anticoagulation with Warfarin for chronic medical conditions. These conditions include, but are not limited to patients with mechanical heart valves, chronic atrial fibrillation, Ventricular Assist Devices (VAD), hypercoagulable states or Deep Venous Thrombosis (DVT).

Before initiation of at-home monitoring, individuals must have undergone anticoagulation management for at least three months.

Additional hardware/software systems needed for down-loading data from prothrombin time home testing units to computers for the management of anticoagulation is not medically necessary.


Individuals who are prescribed chronic warfarin anticoagulation need ongoing monitoring that has generally taken place in a physician’s office or anticoagulation clinic. Home prothrombin monitoring with a U.S. Food and Drug Administration (FDA)-approved device is proposed as an alternative to office or laboratory-based testing.

Prothrombin time home testing systems are portable, battery-operated instruments for the quantitative determination of prothrombin time from finger-stick whole blood. The monitoring device measures the time it takes an individual’s blood to clot. A drop of blood is obtained by a finger-stick using a lancet. The drop of blood is placed on a test strip and analyzed by the device. The device displays both the PT and calculated international normalized ratio (INR). If the results are out of normal range, the individual usually is advised to retest to confirm and if the results remain abnormal, they contact their physician as soon as possible. These devices store 30 - 60 of the most recent test results, which are date and time stamped, enabling the health care provider to review the results and monitor trends in the individual’s oral anticoagulant therapy control.

The goal of home PT monitoring is to help the individual maintain an INR in the desired therapeutic range. International Normalized Ratio (INR) is a system established by the World Health Organization (WHO) and the International Committee on Thrombosis and Hemostasis for reporting the results of blood coagulation (clotting) tests. The INR is the ratio of the individual's prothrombin time compared to the mean prothrombin time for a group of normal individuals. The prothrombin time is the amount of time needed for a small amount of blood to clot.


This policy has been updated regularly with searches of the MEDLINE database. The most recent literature search was performed through November 2022.

Summary of Evidence

Data from multiple RCTs and systematic reviews of RCTs consistently demonstrate that the use of self-monitoring in appropriately trained and motivated patients on long-term anticoagulation therapy results in an increased time in the therapeutic range. Based on prior research, it is likely that time in therapeutic INR is associated with improved health outcomes. Some studies also report a lower rate of hemorrhagic or embolic events, but this evidence is limited by high dropout and noncompliance rates that may have created imbalances between treatment groups. The evidence includes monitoring in several chronic conditions such as mechanical heart valves, chronic atrial fibrillation, and deep venous thrombosis, and therefore comparable results should be able to be obtained in other similar, but less prevalent, conditions that require continuous anticoagulation. During the first few months of anticoagulation, INR levels require frequent monitoring and adjustment of warfarin dose and the risk for adverse events is also higher during this period, particularly for hemorrhagic complications.  Few studies limited enrollment to patients initiating anticoagulation therapy and additional trials are needed to more thoroughly evaluate the safety and efficacy of home prothrombin time monitoring from the start of treatment.  Thus, based on the evidence and clinical context, home prothrombin time monitoring may be considered medically necessary for patients with chronic conditions that require continuous oral anticoagulation with warfarin who are able to self-monitor and who have undergone initial clinic-based anticoagulation management for at least three months.


American College of Chest Physicians (ACCP)

In 2012, the American College of Chest Physicians (ACCP) published evidence-based guidelines on management of anticoagulant therapy. The guidelines include the following recommendations on home prothrombin time testing:

“For patients treated with VKAs (vitamin K antagonists) who are motivated and can demonstrate competency in self-management strategies, including the self-testing equipment, we suggest patient self-management (PSM) rather than usual outpatient INR monitoring (Grade 2B). For all other patients, we suggest monitoring that includes the safeguards in our best practice statement 3.5.”

These safeguards include managing treatment in a systematic and coordinated fashion, educating patients and communicating effectively with patients about test results and dosing decisions.

American Society of Hematology

In 2018, the American Society of Hematology published guidelines for management of venous thromboembolism and optimal management of anticoagulation therapy:

For patients receiving maintenance VKA therapy for treatment of VTE, the ASH guideline panel suggests using home point-of-care INR testing (patient self-testing [PST]) over any other INR testing approach except patient self-management (PSM) (see recommendation 4) in suitable patients (those who have demonstrated competency to perform PST and who can afford this option) (conditional recommendation based on low certainty in the evidence about effects.

U.S. Preventive Services Task Force Recommendations

Not applicable.


Prothrombin time, home prothrombin time monitoring, International Normalized Ratio, INR, mechanical heart valve, ProTime, anticoagulant, warfarin, Coumadin, CoaguChek XS, INRatio, Alere


Home prothrombin monitors have been cleared by the FDA under a 510 (k) process. A 510(k) is a premarketing submission made to FDA to demonstrate that the device to be marketed is as safe and effective, that is, substantially equivalent, to a legally marketed device that is not subject to premarket approval (PMA). Typically, no clinical data is required as part of the 510 (k) application, but instead the clearance process focuses on technical performance. For these devices, however, the FDA granted clearance based upon data demonstrating that properly selected and trained patients, or the caregivers, can generate INR test results comparable to laboratory instruments. These devices must be prescribed by a physician. The PT measured by these devices are granted waived status under the Clinical Laboratory Improvement Act.

In January 2007, the CoaguChek XS System (patient self-testing) (Roche Diagnostics Corporation) was cleared for marketing by the FDA through the 510(k) process.  The FDA determined that this device was substantially equivalent to existing devices including the CoaguChek SX system (professional, cleared in 2006).  Other than a labeling change, the device is identical to the professional version of the CoaguChek XS system.  The patient self-testing system is intended for self-monitoring of prothrombin time in patients who are stabilized on anticoagulation medications.

Other devices cleared by the FDA for home prothrombin time monitoring include the ProTime® Microcoagulation System (International Technidyne Corporation and the Alere™ (formerly Hemosense) INRatio® 2 PT/INR Monitoring System.


Coverage is subject to member’s specific benefits.  Group specific policy will supersede this policy when applicable.

ITS: Home Policy provisions apply

FEP contracts: FEP does not consider investigational if FDA approved and will be reviewed for medical necessity. Special benefit consideration may apply.  Refer to member’s benefit plan.


CPT Codes:

93792 Patient/caregiver training for initiation of home international normalized ratio (INR) monitoring under the direction of a physician or other qualified health care professional, face-to-face, including use and care of the INR monitor, obtaining blood sample, instructions for reporting home INR test results, and documentation of patient's/caregiver's ability to perform testing and report results
93793 Anticoagulant management for a patient taking warfarin, must include review and interpretation of a new home, office, or lab international normalized ratio (INR) test result, patient instructions, dosage adjustment (as needed), and scheduling of additional test(s), when performed

HCPCS codes:

G0248 Demonstration, at initial use, of home INR monitoring for patient with mechanical heart valve (s) who meets Medicare coverage criteria, under the direction of a physician; includes: demonstration use and care of the INR monitor, obtaining at least one blood sample, provision of instructions for reporting home INR test results and documentation of a patient ability to perform testing.
G0249 Provision of test material and equipment for home INR monitoring to patient with mechanical heart valve (s) who meets medicare coverage criteria. Includes provision of materials for use in the home and reporting of test results to physician; per 4 tests (does not require face-to-face service)
G0250  Physician review, interpretation and patient management of home INR testing for a patient with mechanical heart valve (s) who meets other coverage criteria; per 4 tests (does not require face-to-face service)


  1. Bloomfield HE, Krause A, Greer N et al. Meta-analysis: Effect of patient self-testing and self-management of long-term anticoagulation on major clinical outcomes. Ann Intern Med 2011; 154(7): 472-82.
  2. Branson CL, Madsen JS, et al. Home Management of Warfarin Treatment Through a Real-Time Supervised Telemedicine Solution: A Randomized Controlled Trial.Telemed J E Health. 2019 Feb;25(2):109-115. doi: 10.1089/tmj.2017.0260. Epub 2018 Jun 7.
  3. Daniel M. Witt, Robby Nieuwlaat, Nathan P. Clark, Jack Ansell, Anne Holbrook, Jane Skov, Nadine Shehab, Juliet Mock, Tarra Myers, Francesco Dentali, Mark A. Crowther, Arnav Agarwal, Meha Bhatt, Rasha Khatib, John J. Riva, Yuan Zhang, Gordon Guyatt; American Society of Hematology 2018 guidelines for management of venous thromboembolism: optimal management of anticoagulation therapy. Blood Adv 2018; 2 (22): 3257–3291. doi:
  4. DeSantis G, Hogan-Schlientz J, Liska G, et al. STABLE results: warfarin home monitoring achieves excellent INR control. Am J Manag Care. Mar 2014; 20(3):202-209.
  5. Dignan R, Keech AC, Gebski VJ et al. [Warfarin SMART Investigators]. Is home warfarin self-management effective? Results of the randomized Self-Management of Anticoagulation Research Trail. Int J Cardiol. 2013 Oct; 168(6): 5378-5384.
  6. Garcia-Alamino JM, Ward AM, Alonso-Coello P et al. Self-monitoring and self-management of oral anticoagulation. Cochrane Database of Systematic Reviews 2010; (4):CD003839.
  7. Guyatt GH, Akl EA, Crowther M, et al. Executive summary: Antithrombic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines, Chest. 2012 Feb; 141(2_Suppl), 7S-47S.
  8. Heneghan C, Ward A, Perera R et al. Self-monitoring of oral anticoagulation: systematic review and meta-analysis of individual patient data. Lancet 2012; 379(813):322-34.
  9. Holbrook A, Schulman S, Witt DM et al. Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012; 141(2 Suppl):e152S-84S.
  10. Matchar DB, Jacobson A, Dolor R et al. Effect of home testing of international normalized ratio on clinical events. N Engl J Med 2010; 363(17):1608-20.
  11. Matchar DB, Love SR, Jacobson AK, et al. The impact of frequency of patient self-testing of prothrombin time on time in target range within VA Cooperative Study #481: The Home INR Study (THINRS), a randomized, controlled trial. J Thromb Thrombolysis. 2015;40(1):17-25.
  12. National Institute for Health and Care Excellence (NICE). Atrial fibrillation and heart valve disease: Self-monitoring coagulation status using point-of-care coagulometers (the CoaguChek XS system and the INRatio2 PT/INR monitor).  NICE Diagnostics Guidance 14. London, UK: NICE; September 24, 2014.
  13. Thompson JL, Burkhart HM, Daly RC et al. Anticoagulation early after mechanical valve replacement: Improved management with patient self-testing. J Thorac Cardiovasc Surg 2013; 146(3):599-604.


Medical Policy Group, October 2002

Medical Review Committee, October 2002

Medical Policy Administration Committee, November 2002

Available for comment December 18, 2002-February 3, 2003

Medical Policy Group, November 2004 (4)

Medical Policy Group, November 2006 (1)

Medical Policy Group, March 2008 (1)

Medical Policy Administration Committee, March 2008

Available for comment March 19-May 2, 2008

Medical Policy Group, March 2011 (1): Update to Description, Government Approvals, Key Points and References related to MPP update; no change to policy statement

Medical Policy Group, March 2012 (1): Update to Description, Key Points and References related to MPP update; no change to policy statement

Medical Policy Panel, March 2013

Medical Policy Group, June 2013 (1): Updates to Key Points, Government Approvals, and References; removal of criteria prior to 2008 from Policy section, no change to policy coverage criteria

Medical Policy Group, August 2013 (1): Update to Policy with change in coverage criteria that now suggests that home prothrombin time meets medical criteria for coverage for patients who require continuous anticoagulation for chronic medical conditions, including but not limited to mechanical heart valves and chronic atrial fibrillation; no other changes to policy at this time

Medical Policy Administration Committee, August 2013

Available for comment August 21 through October 4, 2003

Medical Policy Panel, March 2014

Medical Policy Group, March 2014 (1): Policy updated with literature search through February 2014; no change in policy statement

Medical Policy Panel, March 2015

Medical Policy Group, March 2015 (6):  Updates to Key Points, Coding and References; no change to policy statement.  Policy remains active but no longer scheduled for regular literature reviews and updates.

Medical Policy Group, December 2017: Annual Coding Update 2018.  Added new CPT codes 93792 and 93793 effective 1/1/18 to Current Coding.  Added Previous Coding section and moved deleted codes 99363 and 99364 to this section.

Medical Policy Group, June 2019 (6): Literature review, updates to Key Points and References. Added Key Word: CoaguChek XS. No change in policy intent.

Medical Policy Group, December 2020 (6): Updates to Policy statement to include non-coverage of software programs for data download, Description, Key Points, Key Words (INRatio, Alere) and References.

Medical Policy Group, December 2021 (6): Updates to Policy Statement to include use of Warfarin and to expand possible covered conditions, Key Points, Governing Bodies, Coding (removed E1399) and References.

Medical Policy Group, November 2022 (6): Updates to Key Points, Practice Guidelines and References.

This medical policy is not an authorization, certification, explanation of benefits, or a contract. Eligibility and benefits are determined on a case-by-case basis according to the terms of the member’s plan in effect as of the date services are rendered. All medical policies are based on (i) research of current medical literature and (ii) review of common medical practices in the treatment and diagnosis of disease as of the date hereof. Physicians and other providers are solely responsible for all aspects of medical care and treatment, including the type, quality, and levels of care and treatment.

This policy is intended to be used for adjudication of claims (including pre-admission certification, pre-determinations, and pre-procedure review) in Blue Cross and Blue Shield’s administration of plan contracts.

The plan does not approve or deny procedures, services, testing, or equipment for our members. Our decisions concern coverage only. The decision of whether or not to have a certain test, treatment or procedure is one made between the physician and his/her patient. The plan administers benefits based on the member’s contract and corporate medical policies. Physicians should always exercise their best medical judgment in providing the care they feel is most appropriate for their patients. Needed care should not be delayed or refused because of a coverage determination.

As a general rule, benefits are payable under health plans only in cases of medical necessity and only if services or supplies are not investigational, provided the customer group contracts have such coverage.

The following Association Technology Evaluation Criteria must be met for a service/supply to be considered for coverage:

1. The technology must have final approval from the appropriate government regulatory bodies;

2. The scientific evidence must permit conclusions concerning the effect of the technology on health outcomes;

3. The technology must improve the net health outcome;

4. The technology must be as beneficial as any established alternatives;

5. The improvement must be attainable outside the investigational setting.

Medical Necessity means that health care services (e.g., procedures, treatments, supplies, devices, equipment, facilities or drugs) that a physician, exercising prudent clinical judgment, would provide to a patient for the purpose of preventing, evaluating, diagnosing or treating an illness, injury or disease or its symptoms, and that are:

1. In accordance with generally accepted standards of medical practice; and

2. Clinically appropriate in terms of type, frequency, extent, site and duration and considered effective for the patient’s illness, injury or disease; and

3. Not primarily for the convenience of the patient, physician or other health care provider; and

4. Not more costly than an alternative service or sequence of services at least as likely to produce equivalent therapeutic or diagnostic results as to the diagnosis or treatment of that patient’s illness, injury or disease.