INR self-monitoring is for patients on long term or lifetime anticoagulation therapy who measure their INR levels themselves, rather than having their levels measured by their healthcare professionals in a clinic. People who self-monitor use a portable monitor which is similar to monitors used in their clinic, to take a drop of blood from their finger at times agreed with their healthcare professionals and record the INR measurement provided by the monitor. You can either self-test or self-manage.
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Patient self-testing
People who are self-testing provide the INR reading they obtain from their monitor to their healthcare professionals at an agreed time, generally by telephone. The healthcare professional decides if any change to the warfarin dose is required and lets the person know what action is needed. A PT/INR meter can be obtained by contacting an Independent Diagnostic Testing Facility (IDTF). They are able to provide patients with all necessary testing equipment and bill the insurance for test results reported.
Patient self-management
People who self manage adjust their warfarin doses themselves, following training with their healthcare professional. This means that if the INR reading obtained from their monitor is out of the normal therapeutic range, they are able to make an adjustment to their own warfarin dose by themselves.
International Normalized Ratio (INR)
International normalized ratio (INR) which is a derivative of prothrombin time is a measurement of blood coagulation in the circulatory system. Both are used to determine the clotting rate of blood which can be affected by anticoagulant usage, liver damage and Vitamin K levels.
The preferred range of INR levels for patient on anticoagulation therapy is usually between 2 and 3, but it tends to vary depending on the patient's requirements.
The advantages of self-monitoring
Patients who self-monitor tend to choose this route for the greater control they feel it gives them over their lives and their condition. This helps to reduce the amount of visits being made to their anticoagulation clinic for routine appointments to measure their INR levels. This is a lengthy process in comparison to self-testing and management.
Results of clinical studies, which have been recognised by the National Patients Safety Authority (NPSA), show that people who self-monitor keep more frequently within their therapeutic range and have fewer complications including clots and bleeding, compared with people who have their INR levels tested only at their anticoagulation clinic.
What the government says about self-monitoring
Patient self-care is a key initiative in the NHS Plan for a patient centred health service and an important component in supporting people with long-term conditions. It is seen to provide:
Who is self-monitoring suitable for?
Self-monitoring may be a suitable option for a variety of people who are on long term anticoagulation therapy and want the convenience of being able to monitor their own INR levels at a time and place of their own choosing (e.g. if travelling abroad either with work or on vacation). They do have continuous support from their healthcare professionals and there are no upper age limits for self-monitoring and parents can take charge for their children.
Self-monitoring is ideal if:
Clinical Trials
In the past 5 years, there have been a number of clinical trials to highlight the advantages of self-monitoring whether self-testing or self-managing. It also gives an indication of what improvements the self-testing and self-management can do to INR levels.
What the clinical studies say about INR self-monitoring
"Quality of life changed in a positive way. Independence and better organisation of vacation and spare time were most frequently mentioned advantages."
Extract from a study into the impact of self-monitoring on the quality of life of anticoagulation patients.
"Patient self-testing...is an effective method of monitoring oral anticoagulation therapy, providing outcomes at least as good as, and possibly better than, those achieved with an anticoagulation clinic."
From international consensus guidelines prepared by the International Self-Monitoring Association for Oral Anticoagulation.
"Self-monitoring can improve the quality of oral anticoagulation therapy, with patients more frequently in the therapeutic range, while improving benefits and decreasing harms."
From the conclusions of a review of a number of studies of self-monitoring in oral anticoagulation.
In another randomized controlled trial comparing whether INR weekly home testing offers an advantage over high-quality clinic testing in reducing the risk of a major event (stroke, major bleeding episode, or death), the results showed that the time to the first primary event (stroke, major bleeding episode, or death) was not significantly longer in the self-testing group than in the clinic testing group (hazard ratio, 0.88; 95% confidence interval, 0.75 to 1.04; p=0.14). The study is designed as a prospective, randomized, nonblinded trial. Patients were randomized into two groups (weekly self testing vs monthly clinic testing) using an adaptive-allocation stratification method according to the duration of anticoagulation and indication for warfarin. Although the study was nonblinded, blinding is less critical because the outcomes of the study were objective (stroke, major bleeding episode, death).
Monitors
Patients who are self-monitoring have to use a monitor in order to measure their INR level. There are range of INR testing monitors on the market such as the CoaguChek XS, microINR., INRatio2, and qLabs