Prothrombin time self-monitoring devices, also referred to as International Normalized Ratio (INR) devices, are battery-operated devices used by individuals in the home to monitor blood-clotting rates. Home prothrombin time self-monitoring permits frequent measurement and self-management of anticoagulant therapy (e.g., warfarin) with the ultimate goal of increasing the time that anticoagulation is within a therapeutic INR range while decreasing the incidence of thromboembolic or hemorrhagic events. The most common indications for chronic oral anticoagulation therapy are for individuals with mechanical heart valves, chronic atrial fibrillation, or venous thromboembolism (inclusive of deep venous thrombosis and pulmonary embolism).

Medically Necessary:

Home prothrombin time self-monitoring using an INR device is considered medically necessary for an individual who meets all of the following criteria:

1. Requires long term (greater than one year) anticoagulation with warfarin; and
2. Requires at least weekly determinations of INR values; and
3. The treating physician prescribes the self-monitoring device and home testing.

Note:

• An individual or caregiver who undertakes self-monitoring must demonstrate the technical skill and willingness to use the monitor and the ability to comprehend the basic aspects of oral anticoagulation control, including the risks.
• Compliance and cooperation are primary factors in the selection of appropriate candidates for home prothrombin time self-monitoring.
• Individual or caregiver training for home prothrombin time self-monitoring is provided under physician supervision. The training must, at a minimum, consist of:
  • Demonstrating use and care of the INR monitor;
  • Obtaining at least one blood sample;
  • Providing instructions for reporting home INR test results; and
  • Documentation of the ability to perform testing.  

Not Medically Necessary:  

Home prothrombin time self-monitoring is considered not medically necessary for an individual who does not meet the above criteria.

The following codes for treatments and procedures applicable to this document are included below for informational purposes.  A draft of future ICD-10 Coding (effective 10/01/2014) related to this document, as it might look today, is included below for your reference.  Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy.  Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

A prothrombin time self-monitoring system is a battery-operated device used to monitor blood-clotting rates by an individual in the home setting. Each of these systems includes a monitor, a disposable plastic reagent cartridge and a finger stick blood collection kit. The device stores between 30-40 of the most recent test results, which are date and time-stamped. This enables the physician, individual, and/or caregiver the ability to review the results and monitor trends in the individual's oral anticoagulant therapy control. After testing, the individual either notifies the physician of the results or uses an individualized algorithm, developed with physician supervision, to adjust the anticoagulation dosage (warfarin sodium/Coumadin^®_, Bristol-Myers Squibb, Princeton, NJ) to maintain prothrombin time levels within a target zone. The goal of self-monitoring and self-management of prothrombin time levels is to improve anticoagulation control and reduce the frequency of adverse events. Several U.S. Food and Drug Administration (FDA) approved prothrombin time self-monitoring devices are available for use in the home including, but not limited to: CoaguSense™ Self-Test PT/INR Monitoring System (CoaguSense, Inc., Fremont, CA), ProTime^® Microcoagulation System (International Technidyne Corporation, Edison, NJ), CoaguChek^® XS System for Patient Self-Testing (PST) (Roche Diagnostics-North America, Indianapolis, IN), CoagCare^® (ZyCare^® Inc, Chapel Hill, NC), and Alere™ INRatio^®/INRatio2^® PT/INR Monitoring Systems (Alere Inc., Waltham, MA). Home prothrombin time self-monitoring devices require a prescription for use. The prescribing physician is responsible for the training and ongoing management of individuals selected for self-monitoring.

Oral anticoagulant drugs have been used in the prophylaxis and treatment of venous thrombosis, pulmonary embolus, thromboembolic complications of atrial fibrillation, prosthetic heart valve replacement, and to prevent recurrent myocardial infarctions and transient ischemic attacks. In the United States, Coumarin derivatives are the most commonly used oral anticoagulants and include warfarin sodium (Coumadin) and dicumarol. All oral anticoagulants have a narrow therapeutic index. Changes in diet, drug interactions, illness, individual differences, and spontaneous fluctuations in the sensitivity to oral anticoagulant influence the dose-response relationships for these drugs. As a result, oral anticoagulant therapy requires individualized treatment for each person and frequent blood coagulation monitoring to prevent serious bleeding from too much anticoagulation or thromboembolic complications from inadequate coagulation.

The anticoagulant effect of warfarin should be kept at an international normalized ratio (INR) of about 2.5 (desirable range, 2.0-3.0), although a higher level may be better in certain clinical conditions, such as in individuals with prosthetic heart valves. The risk of bleeding increases exponentially with INR and becomes clinically unacceptable once the INR exceeds 5.0. Major bleeding has been reported in 1.1%-8.1% of individuals during each year of long-term warfarin therapy. Risk factors include the individual's age (i.e., elderly), serious illness (e.g., cerebral, cardiac, kidney or liver disease), cerebrovascular or peripheral vascular disease, and an unstable anticoagulant effect.

The studies reviewed evaluate individuals with a variety of indications for anticoagulation therapy. The majority of individuals received anticoagulation therapy for prosthetic heart valve replacement. Studies also included individuals with deep venous thrombosis, atrial fibrillation, total hip arthroplasty, and history of pulmonary emboli. Controlled studies show prothrombin time self-monitoring devices are effective in maintaining the INR values within a therapeutic range. None of the studies indicate a decrease in anticoagulation control and many indicate improved anticoagulation control with home monitoring devices. Such improvement is thought to be due to several factors. Prothrombin time testing intervals in the self-monitored individual are performed weekly as compared to every two weeks to monthly intervals when performed by a physician. The complications associated with self-monitoring appear to be equivalent to or less than those associated with anticoagulation therapy monitored by a physician or a specialized clinic. When individuals are given proper training and support, the cumulative evidence from clinical trials suggests that prothrombin time self-monitoring with a home testing device is accurate, feasible, and possibly more effective than standard laboratory prothrombin time testing in maintaining anticoagulation control within target therapeutic ranges. In the studies evaluated, the results obtained with prothrombin time self-monitoring do not appear to vary with the individual's diagnosis. The individuals in the cited studies had conditions requiring long-term anticoagulation.

The FDA approval of home prothrombin time self-monitoring devices is based on the demonstration that home prothrombin monitors produce results similar to laboratory-based measurements. The FDA approval did not require clinical data demonstrating that the increased frequency of home self-monitoring would improve health outcomes. Several randomized studies have reported improved health outcomes (primarily increased time in the therapeutic range) associated with home self-monitoring and management compared to monitoring either in a physician's office or in a specialty anticoagulation clinic. A Cochrane meta-analysis (Garcia-Alamino, 2010) reported on a pooled estimate of 18 randomized controlled trial (4723 participants), showing significant reductions in both thromboembolic events (risk ratio [RR] 0.50, 95% confidence interval [CI] 0.36 to 0.69) and all-cause mortality (RR 0.64, 95% CI 0.46 to 0.89). Trials of self-management alone showed significant reductions in thromboembolic events (RR 0.47, 95% CI 0.31 to 0.70) and all-cause mortality (RR 0.55, 95% CI 0.36 to 0.84); self-monitoring did not (thrombotic events RR 0.57, 95% CI 0.32 to 1.00; mortality RR 0.84, 95% CI 0.50 to 1.41). Self-monitoring significantly reduced major hemorrhages (RR 0.56, 95% CI 0.35 to 0.91) while self-management did not (RR 1.12, 95% CI 0.78 to 1.61). Twelve trials reported improvements in the percentage of mean INR measurements in the therapeutic range. No heterogeneity was identified in any of these comparisons. The authors concluded that compared to standard monitoring, individuals who self-monitor or self-manage can improve the quality of their oral anticoagulation therapy. The number of thromboembolic events and mortality were decreased without increases in harms. However, self-monitoring or self-management were not feasible for up to half of the individuals requiring anticoagulant therapy due to refusal to participate, exclusion by their general practitioner, and inability to complete training.

Bloomfield and colleagues (2011) published a meta-analysis and systematic review that included randomized controlled trials with adult subjects comparing home monitoring to monitoring in a physician's office or anticoagulation clinic; studies included adults receiving long-term (greater than three months) therapy. The systematic reviews identified 22 trials; five on self-monitoring only and 14 that included self-management. In a pooled analysis, there were significantly fewer major thromboembolic events in the self-monitoring and self-management group (99 of 4004 subjects, 2.5%) compared to the standard treatment group (149 of 3755 subjects, 4.0%; odds ratio [OR]: 0.58 (95% CI: 0.45 to 0.75). Rates of major bleeding events did not differ significantly in the two groups. Similar to the Cochrane meta-analysis (Garcia-Alamino, 2010), the authors noted the low rate of study participation in subjects who met preliminary eligibility criteria. The authors did not conduct separate analysis of studies that did and did not enroll inception cohorts.

Heneghan and colleagues (2012) published a meta-analysis using a design similar to the other published meta-analyses. The investigators searched for randomized controlled trials comparing self-monitoring or self-management of oral anticoagulation by adults compared to management by a physician or anticoagulation clinic. This review did not discuss the issue of whether or not home monitoring occurred in the initial three months of anticoagulation therapy. The meta-analysis included data on 6,417 participants from 11 of the eligible 21 trials. In a pooled analysis, there was a statistically significant reduction in thromboembolic events in the home prothrombin time when the protime monitoring group was compared to the standard therapy group (hazard ratio [HR]: 0.51, 95% CI: 0.31 to 0.85). There was not a significant difference between groups in the rate of major hemorrhagic events (HR: 0.88, 95% CI: 0.74 to 1.06) or death (HR: 0.82, 95% CI: 0.62 to 1.09).

Effective March 19, 2008, the Centers for Medicare and Medicaid Services (CMS) implemented a National Coverage Determination (NCD) for Home Prothrombin Time Monitoring for Anticoagulation Management.Coverage indications include "the use of home PT/INR monitoring for chronic, oral anticoagulation management for patients with mechanical heart valves, chronic atrial fibrillation, or venous thromboembolism (inclusive of deep venous thrombosis and pulmonary embolism) on warfarin" (CMS, 2008). The coverage determination includes specific participant selection criteria and monitoring by the prescribing physician.

International Normalized Ratio (INR): A standardized system established by the World Health Organization (WHO) and the International Committee on Thrombosis and Hemostasis (ICTH) for reporting the results of blood coagulation (clotting) tests using the international sensitivity index for the particular thromboplastin reagent and instrument combination utilized to perform the test.

Prothrombin Time (PT): A test belonging to a group of blood tests that assess the clotting ability of blood; also known as the protime or PT test.

Peer Reviewed Publications:

1. Beyth RJ, Quinn L, Landefeld CS. A multicomponent intervention to prevent major bleeding complications in older patients receiving warfarin. A randomized, controlled trial. Ann Intern Med. 2000; 133(9):687-695.
2. 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): 472-482.
3. Christensen TD, Johnsen SP, Hjortdal VE, Hasenkam JM. Self-management of oral anticoagulant therapy: a systematic review and meta-analysis. Int J Cardiol. 2007; 118(1):54-61.
4. Cromheecke ME, Levi M, Colly LP, et al. Oral anticoagulation self-management and management by a specialist anticoagulation clinic: a randomized cross-over comparison. Lancet. 2000; 356(9224):97-102.
5. Dolor RJ, Ruybalid RL, Uyeda L, et al. An evaluation of patient self-testing competency of prothrombin time for managing anticoagulation: pre-randomization results of VA Cooperative Study #481--The Home INR Study (THINRS). J Thromb Thrombolysis. 2010; 30(3):263-275.
6. Eldor A, Schwartz J. Self-management of oral anticoagulants with a whole blood prothrombin-time monitor in elderly patients with atrial fibrillation. Pathophysiol Haemost Thromb. 2002; 32(3):99-106.
7. Engh CA Jr, Culpepper WJ 2nd, Charette PA, Brown R. Patient self-testing of prothrombin time after hip arthroplasty. J South Orthop Assoc. 2001; 10(3):140-146.
8. Finsterer J, Stollberger C, Hopmeier P. Home-made anticoagulation monitor vs CoaguCheck-Plus monitoring of oral anticoagulation. Thromb Res. 2000; 98(6):571-575.
9. Fitzmaurice DA, Murray ET, McCahon D, et al. Self management of oral anticoagulation: randomised trial. BMJ. 2005; 331:1057-1059. Erratum in: BMJ. 2005; 331(7528):1330.
10. Gardiner C, Longair I, Pescott MA, et al. Self-monitoring of oral anticoagulation: does it work outside trial conditions? J Clin Pathol. 2009; 62(2):168-171.
11. Gardiner C, Williams K, Longair I, et al. A randomized control trial of patient self-management of oral anticoagulation compared with patient self-testing. Br J Haematol. 2006; 132(5):598-603.
12. Heidinger KS, Bernardo A, Taborski U, Muller-Berghaus G. Clinical outcome of self-management of oral anticoagulation in patients with atrial fibrillation or deep vein thrombosis. Thromb Res. 2000; 98(4):287-293.
13. Heneghan C, Alonso-Coello P, Garcia-Alamino JM, et al. Self-monitoring of oral anticoagulation: a systematic review and meta-analysis. Lancet. 2006; 367(9508):404-411.
14. 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):322-334.
15. Koertke H, Zittermann A, Wagner O, et al. Efficacy and safety of very low-dose self-management of oral anticoagulation in patients with mechanical heart valve replacement. Ann Thorac Surg. 2010; 90(5):1487-1493.
16. Massicotte P, Marzinotto V, Vegh P, et al. Home monitoring of warfarin therapy in children with a whole blood prothrombin time monitor. J Pediatr. 1995; 127(3):389-394.
17. 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):1608-1620.
18. Matchar D, Jacobson A, Edson R, et al. The impact of patient self-testing of prothrombin time for managing anticoagulation: rational and design of VA Cooperative Study #481-the Home INR Study (THINRS). J Thromb Thrombolysis. 2005; 19(3):163-172.
19. Menendez-Jandula B, Souto JC, Oliver A, et al. Comparing self-management of oral anticoagulant therapy with clinic management: a randomized trial. Ann Intern Med. 2005; 142(1):1-10.
20. Murray ET, Jennings I, Kitchen D, et al. Quality assurance for oral anticoagulation self management: a cluster randomized trial. J Thromb Haemost. 2008; 6(3):464-469.
21. Oral Anticoagulation Monitoring Study Group. Prothrombin measurement using a patient self-testing system. Am J Clin Pathol. 2001; 115(2):280-287.
22. Quin J, Rogers LQ, Markwell S, et al. Home-anticoagulation testing: accuracy of patient-reported values. J Surg Res. 2007; 140(2):189-193.
23. Sawicki PT. A structured teaching and self-management program for patients receiving oral anticoagulation: a randomized controlled trial. JAMA. 1999; 281(2):145-150.
24. Siebenhofer A, Rakovac I, Kleespies C, et al. Self-management of oral anticoagulation in the elderly: rationale, design, baselines and oral anticoagulation control after one year of follow-up. A randomized controlled trial. Thromb Haemost. 2007; 97(3):408-416.
25. Voeller H, Dovifat C, Wegscheider K. Experience with INR self-management: patient selection and complication rates. Z Kardiol. 2005; 94(12):801-807.
26. Völler H, Glatz J, Taborski U, et al. Self-management of oral anticoagulation in nonvalvular atrial fibrillation (SMAAF study). Z Kardiol. 2005; 94(3):182-186.
27. Watzke HH, Forberg E, Svolba G, et al. A prospective controlled trial comparing weekly self-testing and self-dosing with the standard management of patients on stable oral anticoagulation. Thromb Haemost. 2000; 83(5):661-665.

Government Agency, Medical Society, and Other Authoritative Publications

1. Ansell J, Hirsh J, Hylek E, et al. American College of Chest Physicians (ACCP). 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.
2. Centers for Medicare and Medicaid Services (CMS). National Coverage Determinations. Available at: http://www.cms.hhs.gov/mcd/index_list.asp?list_type=ncd#PP. Accessed on December 3, 2012.
   • Home Prothrombin Time INR Monitoring for Anticoagulation Management. NCD #190.11. Revised March 19, 2008.
   • Prothrombin Time (PT). NCD #190.17. Effective November 25, 2002.
3. Connock M, Stevens C, Fry-Smith A, et al. Clinical effectiveness and cost-effectiveness of different models of managing long-term oral anticoagulation therapy: a systematic review and economic modeling. Health Technol Assess. 2007; 11(38):iii-iv, ix-66.
4. Garcia-Alamino JM, Ward AM, Alonso-Coello P, et al. Self-monitoring and self-management of oral anticoagulation. Cochrane Database Syst Rev. 2010; (4):CD003839.
5. U.S. Food and Drug Administration (FDA). Center for Devices and Radiological Health: Device Summary Information. IVD Database: Prothrombin. Available at: http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfivd/index.cfm.  Accessed on December 3, 2012.

Alere INRatio/INRatio2 PT/INR Monitoring Systems
CoagCare Anticoagulation Management System
CoaguChek XS System
Coagu-Sense Self-Test PT/INR Monitoring System
ProTime Microcoagulation System

The use of specific product names is illustrative only. It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available.