BlueCross and BlueShield of Montana Medical Policy/Codes
Home Prothrombin Time Monitors
Chapter: Durable Medical Equipment
Current Effective Date: July 18, 2013
Original Effective Date: November 07, 2008
Publish Date: April 18, 2013
Revised Dates: March 1, 2010, June 1, 2011; June 27, 2012; April 17, 2013

Warfarin is an effective anticoagulant for the treatment and prevention of venous and arterial thrombosis.  Chronic warfarin therapy is recommended in all patients with mechanical heart valves and in some patients with chronic atrial fibrillation (i.e., patients with one high-risk factor or more than one moderate-risk factor).  Patients with mechanical heart valves are frequently anticoagulated at higher levels than for other indications, which puts them at higher risk of complications from warfarin therapy.  Appropriate levels of warfarin anticoagulation are monitored with periodic prothrombin time measurements, as measured by the International Normalized Ratio (INR).  For example, an INR >3 results in a higher risk of serious hemorrhage, while an INR of six increases the risk of developing a serious bleed nearly seven times that of someone with INR less than three.  In contrast, an INR below two is associated with increased risk of stroke.  Therefore, monitoring of the prothrombin times is recommended to ensure that the dose levels are within the therapeutic range.

There are at least three sites of monitoring anticoagulation:

  • Physician's office (80%): usually once a month;
  • Anticoagulation clinics (20%): usually once every 2-3 weeks; or
  • Home: prothrombin time monitors (<5%).

There are several different devices approved by the U. S. Food and Drug Administration (FDA) that may be purchased by the patient for in-home monitoring of chronic anti-coagulant therapy.  The FDA approval for all of these devices was based on the demonstration that appropriately trained patients could generate INR test results comparable to laboratory measures. However, the clinical impact of home prothrombin time monitoring is related to improved warfarin management.  Specifically, home prothrombin time monitoring permits more frequent monitoring and self-management of warfarin therapy with the ultimate goal of:

  • Increasing the time that the anticoagulation is within a therapeutic INR range (intermediate health outcome); and
  • Decreasing the incidence of thromboembolic or hemorrhagic events (final health outcome).

Home self-monitoring is typically associated with some form of self-management of warfarin therapy.  In some cases, the patient may be supplied with treatment algorithms and instructed to alter the dose based on the results of self-monitoring.  In other cases, the patient may be instructed to telephone in the results of the self-monitoring and receive further telephonic instructions on warfarin dose. 


Each benefit plan, summary plan description or contract defines which services are covered, which services are excluded, and which services are subject to dollar caps or other limitations, conditions or exclusions. Members and their providers have the responsibility for consulting the member's benefit plan, summary plan description or contract to determine if there are any exclusions or other benefit limitations applicable to this service or supply.  If there is a discrepancy between a Medical Policy and a member's benefit plan, summary plan description or contract, the benefit plan, summary plan description or contract will govern.

Medically Necessary

BCBSMT may consider prothrombin time (PT) home monitoring devices medically necessary when used as an adjunct to regulation of anti-coagulant therapy in high-risk members that includes:

  • Patients with mechanical heart valves who have been stable on anticoagulation management for at least three months; OR
  • Patients with chronic atrial fibrillation or pulmonary embolism on warfarin; OR
  • Patients with venous thromboembolism, inclusive of deep venous thrombosis; OR
  • Patients with a hypercoagulable state, including but not limited to:
    • Antithrombin III deficiency,
    • Protein C deficiency,
    • Protein S deficiency,
    • Activated Protein C resistance (Factor V Leiden),
    • Antiphospholipid syndrome,
    • Prothrombin 20210 defect,
    • Dysfibrinolysis,  AND

In addition to the above indications, the patient must:

  • Have an anticipated length of need of greater than six months; and
  • Have been anticoagulated for at least three months prior to use of the home International Normalized Ratio INR device; and,
  • Undergo a face-to-face educational program on anticoagulation management and must have demonstrated the correct use of the device prior to its use in the home; and,
  • Continue to correctly use the device in the context of the management of the anticoagulation therapy following the initiation of home monitoring; and,
  • Perform self-testing with the device not to occur more frequently than once a week.

Not Medically Necessary

BCBSMT considers prothrombin time (PT) home monitoring devices not medically necessary if the above criteria are not met.


Since the original publication of this policy in 1999, several randomized studies have compared home prothrombin time monitoring to either monitoring in a physician's office or monitoring in specialized coagulation clinics.  As with any monitoring technology, one would ideally like to isolate the contribution of the monitored data itself from the possible impact of increased patient education or contact with health professionals that is typically associated with more intense monitoring.  Final health outcomes would ideally focus on the incidence of hemorrhagic or embolic events.  However, due to the low incidence of these events, published studies have primarily focused on the intermediate outcome of time spent in the therapeutic range of warfarin, as measured by the International Normalized Ratio (INR).

Results of eight randomized controlled trials including over 2,000 patients have been published, and all have shown that self-monitoring and management was associated with an increase in the PT "time in therapeutic range" (TTR) from 6% to 34%.  Two of the larger trials also reported a decrease in adverse outcomes.  For example, Beyth and colleagues reported on a study that randomized 325 patients who started warfarin therapy during hospitalization to a self-monitoring and management group or a usual care group.  The self-monitoring group received patient education about warfarin training to increase patient participation, self-monitoring of prothrombin time, and guideline-based management.  At six months, the authors showed a lower rate of major hemorrhage in the self-monitoring group (5.7%) compared to the control group (12%) (p=0.049).  After six months, there was no difference in the frequency of major bleeding between the two groups.  The time in therapeutic range also increased in the self-monitoring group, from 32% in the usual care group to 56% in the self-monitoring group.

The Early Self-Controlled Anticoagulation Trial (ESCAT) is a trial of 1,200 patients who received mechanical heart valves and were randomized to either patient self-testing and management or usual care.  Results of the first 200 patients who have been followed up for two years have been published.  The authors evaluated complications on an IV-grade scale.  For example, grade III was defined as a complication requiring hospitalization.  In the treatment group, 9.5% required hospitalization compared to 15.3% in the usual care group, a 40% reduction.

In summary, the data consistently demonstrate that the use of self-monitoring and self-management results in an increased time in the therapeutic range, possibly leading to a reduction in hemorrhagic or embolic events.  Since patients with mechanical heart valves represent the majority of patients studied so far, and since these patients are taking anticoagulates at higher levels, this subset of patients is most likely to benefit from self-monitoring and management.

A study by Eldor and Schwartz evaluated home prothrombin time monitoring in 20 elderly patients with atrial fibrillation with 20 matched controls for 12 months.  The study authors reported fewer PT values above or below the therapeutic range and high satisfaction in the study group.  However, the median recorded PT value for both groups was within the therapeutic range.  In addition, no hemorrhagic or thrombotic events occurred in either group.  The authors concluded that home monitoring of anticoagulate therapy is feasible in a motivated population.  Nevertheless, this study did not demonstrate greater improvements in health outcomes with home monitoring over traditional treatment in this population.

2008 Update

The policy was updated with a literature search through MEDLINE in January 2008.  A number of studies have reported on home monitoring and patient self-monitoring in chronic oral anti-coagulation with warfarin for conditions other than artificial heart valves.  The results of 10 randomized studies were recently summarized.  This report indicates that the literature demonstrates in some populations (mechanical heart valves, chronic atrial fibrillation, and venous thrombosis) the use of the home INR monitor is at least equivalent to laboratory testing or physician office testing with respect to time in treatment range (TTR).  This report also comments on the low rate of adverse thromboembolic and hemorrhagic events in this population and indicated that while two of the studies reviewed showed decreased rates, the others did not. This report also commented on the concerns about selection bias and low enrollment rates in these studies.  They questioned whether results would generalize beyond patients who have demonstrated capability and motivation for undergoing self-management and for ongoing use of the device over time.

In one of the studies reviewed, Fitzmaurice randomized 617 patients aged over 18 and receiving warfarin (about 50% for atrial fibrillation) to intervention and routine care.  Intervention patients used a point of care device to measure INR twice a week and a simple dosing chart to interpret their dose of warfarin.  No significant differences were found in percentage of time in the therapeutic range between self management and routine care (70% vs. 68%).  Self managed patients with poor control before the study showed an improvement in control that was not seen in the routine care group.  Nine patients (2.8/100 patient years) had serious adverse events in the self managed group, compared with seven (2.7/100 patient years) in the routine care arm.  The authors concluded that with appropriate training, self management is safe and reliable for a sizable proportion of patients receiving oral anticoagulation and may improve the time spent in the therapeutic range for patients with initially poor control.

In a European study, Menendez-Jandula reported on 737 patients with indications (about half had atrial fibrillation) for anticoagulant treatment.  The self-management group (n = 368) received simple instructions for using a portable coagulometer weekly and self-adjusting treatment dose. The conventional management group (n = 369) received usual care in an anticoagulation clinic (monthly measurement and control of INR, managed by hematologists).  The median follow-up period was 11.8 months.  The unadjusted percentages of in-range INRs were 58.6% in the self-management group and 55.6% in the conventional management group (95% CI for difference, 0.4 to 5.4 percentage points).  Twenty-seven patients (7.3%) in the conventional management group and eight (2.2%) in the self-management group had major complications related to anticoagulant treatment; the unadjusted risk difference for major complications between groups was 5.1 percentage points (95% CI, 1.7 to 8.5 percentage points).  This trial was performed at only one center and was not blinded. The dropout rate in the intervention group was 21%.

2010 Update

The ESCAT trial included patients who were first managed in anticoagulation clinics and were stabilized on warfarin before they started home self-monitoring.  

In 2009, Gardiner and colleagues published a prospective cohort study from the U.K. evaluating the acceptability and efficacy of home prothrombin time monitoring from the start of treatment.  Patients believed to be unsuitable for self-monitoring were ineligible; this included individuals with known drug or alcohol abuse, atypical INR target ranges, anticipated short duration of anticoagulation or physical or intellectual impairment that could impede self-monitoring.  A total of 188 of 318 (59%) consecutive patients referred for oral anticoagulation were considered eligible for self-monitoring and were offered the choice of self-monitoring or routine hospital anticoagulation.  Of these, 84 (44%) chose to self-monitor.  Seventy-two patients completed training and started self-monitoring; 26 completed their course of oral anticoagulation during the study period and 42 were still self-monitoring at the end of the study period; four patients had incomplete data.  Data from 67 out of the 84 (80%) patients who chose to self-monitor were included in the analysis. Among the 104 patients who elected for routine anticoagulation, only 88 (85%) had sufficient data available to be included in the analysis.  The median percent time spent in therapeutic range was 71% (95% CI: 64–75%) for the 67 self-monitoring patients and 60% (95% CI: 55–63%) for the 88 routine care patients; this difference was statistically significant (p=0.003).  In the self-monitoring group, the incidence of adverse events included 1.7 major bleeds per 100 patient-years of follow-up, 8.4 minor bleeds per 100 patient-years, and 3.4 thromboses per 100 patient-years.  In the routine care group, there were 5.4 major bleeds per 100 patient-years of follow-up, 16.2 minor bleeds per 100 patient-years, and 1.4 thromboses per 100 patient-years.  A limitation of the study was that patients were not randomized to treatment group and there may have been differences in those who chose or did not choose to self-monitor (e.g., motivation) that affected outcomes.  One demographic difference was that patients in the self-monitoring group were significantly younger than those receiving routine coagulation, and thus may have a greater likelihood of good outcomes.  The study was funded by Roche, the manufacturer of clinic- and home-based prothrombin time monitors.  Randomized trials with sufficient large samples are needed to evaluate the safety and efficacy of home prothrombin time monitoring from the start of treatment.

Technology Assessments, Guidelines and Position Statements

In 2008, the American College of Chest Physicians (ACCP) published evidence-based guidelines on management of vitamin K antagonists.  These guidelines included a statement that patient self-testing can be an effective alternative treatment model in patients who are suitably selected and trained.


The data consistently demonstrate that the use of self-monitoring and self-management, in patients initially managed in a clinical setting, results in an increased time in the therapeutic range, possibly leading to a reduction in hemorrhagic or embolic events.  The evidence is consistent overall for home anticoagulation 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.  The evidence is insufficient to conclude that the use of initial self-monitoring improves the net health outcome.  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 have undergone initial clinic-based anticoagulation management.


Disclaimer for coding information on Medical Policies         

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive.           

The presence or absence of procedure, service, supply, device or diagnosis codes in a Medical Policy document has no relevance for determination of benefit coverage for members or reimbursement for providers. Only the written coverage position in a medical policy should be used for such determinations.           

Benefit coverage determinations based on written Medical Policy coverage positions must include review of the member’s benefit contract or Summary Plan Description (SPD) for defined coverage vs. non-coverage, benefit exclusions, and benefit limitations such as dollar or duration caps.

ICD-9 Codes

286.3, 289.81, 415.1, 415.11, 415.12, 415.19, 416.2, 427.31, 453.40, 453.41, 453.42, 453.50, 453.51, 453.52, V43.3, V58.61

ICD-10 Codes
Procedural Codes: 99363, 99364, G0248, G0249, G0250
  1. Centers for Medicare and Medicaid Services (CMS) Decision Memorandum: Home prothrombin time (INR) monitor for anticoagulation management.  Available at .
  2. Beyth, R.J., Quinn, L., et al.  A multicomponent intervention to prevent major bleeding complications in older patients receiving warfarin.  A randomized controlled trial.  Annals of Internal Medicine (2000) 133(9):687-95.
  3. Koertke, H., Minami, K., et al.  INR self-management following mechanical heart valve replacement.  Journal of Thrombosis and Thrombolysis (2000) 9 (supplement1) S41-5.
  4. Eldor, A., and J. Schwartz.  Self-management of oral anticoagulants with a whole blood prothrombin-time monitor in elderly patients with atrial fibrillation.  Pathophysiology Haemostasis Thrombosis (2002) 32(3):99-106.
  5. Yang, D.T., Robetorye, R.S., et al.  Home prothrombin time monitoring: a literature analysis.
  6. American Journal of Hematology (2004 Oct.) 77(2): 177-86.
  7. Fitzmaurice, D.A., Murray, E.T., et al.  Self management of oral anticoagulation: randomised trial.  British Medical Journal (2005) 331(7524):1057.
  8. Menendez-Jandula, B., Souto, J.C., et al.  Comparing self-management of oral anticoagulant therapy with clinic management: a randomized trial.  Annals of Internal Medicine (2005) 142(1):1-10
  9. Prothrombin Time (PT/INR) Monitoring for Home Anticoagulation Management.  Centers for Medicare & Medicaid Services (CMS) Change Request 6138.  Pub 100-03 Medicare National Coverage Determinations Transmittal 90 (2008 July 25). 
  10. Ansell, J., Hirsh, J., et al. Pharmacology and management of the vitamin K antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest (2008)133(6 Suppl):160S-198S.
  11. Gardiner, C., Longair, I., et al. Self-monitoring of oral anticoagulation: does it work outside trial conditions? J Clin Pathol (2009) 62(2):168-71.
  12. Home Prothrombin Time Monitoring.  Chicago, Illinois:  Blue Cross Blue Shield Association Medical Policy Reference Manual (2010 Mar.) Durable Medical Equipment 1.01.14.
June  2011 Updated rationale and references
June 2012 Policy updated with literature search; reference numbers 2, 3, 8-10 added; other references renumbered/removed; no change in policy statement
April 2013

Title changed from "Home Prothrombin Time INR Monitoring for Anticoagulation Management" to "Home Prothrombin Time Monitors".  Additional criteria added to the Medically Necessary statement.  Rationale and formatting revised.

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Home Prothrombin Time Monitors