I write this as a well controlled, proactive type 2 diabetic who uses self-testing of my blood glucose several times a day, particularly post prandial as well as FBG.  What seems to make self-testing work is good knowledge of why you are testing and what you should be doing with the results.  too many people may well test, but not really apply the results to to their eating or activity patterns.  Knowledge of what to to with a high or low reading, hopefully, with some understanding of the underlying causes of these reading is essential for self testing to work.  Too often people test and report number without knowing what to do with them.  This could well explain the VA results, as I fear is the case with many of the studies on diabetic self-testing as not being helpful .  

My opinion is that the self-testing should work well with motivated people who are willing to learn and understand what the inr is telling them and how to adjust it.  With geriatric populations, mental state of the patient and spouse should be monitored to determine if this understanding is possible for patient of caretaker.

I've been testing my INR weekly for 18 months and it has enabled me to remain in range (2-3) virtually 100% of the time. I have self adjusted my warfarin some times when I can see it edging down or up. I have had very little support from the local anti-coag clinic, who do not consider a change of warfarin until results are significantly out of range. If I had relied on their results I would have been seriously under-coagulated for about 2 months recently.

 Dr Goldhaber is right, I feel very empowered by my monitor and take great interest in my INR results and the impact change of diet etc. has.

I had to pay for my monitor but the test strips are free through the NHS. It's still the best thing I've bought in a long time.

My husband takes warfarin to reduce stroke risk from paroxymal Afib, and because he has some significant LV dysfunction due to a previous MI.

 We found the anti-coag clinic to be not as useful, or effective, as in-home testing. The longish intervals between scheduled testing (4-5 weeks) left us with no confirming info at the onset of a new bout of AF, particularly on weekends or holidays.  

 We wanted  the tightest control of INR levels possible.  Anyone who has actually taken warfarin knows that the chief problem is the variable amount of Vitamin K in food.  It's absurd to suggest anyone can realistically judge the amount  of Vit. K. in food because a) the data is contradictory, and b) the levels fluctuate siginifcantly depending on uncontrollable factors such as variety, place of origin, storage conditions and age of food. The result is INR levels that can fluctuate over the course of a day or two unless you rigidly restrict your diet.  (And even then there are surprises!)

Since some of the most healthy foods are also the most problematic as far as Vit. K., and we were determined to combine a tasty, healthy diet with excellent INR levels, we decided we had no choice except home-testing.  We investigated the home-testing services but were put off by home-testing that simply was a passive system: you test and call in results to a service -an expensive one at that - and await a call about changing the dosage. These usually restrict the number of tests per month, as well. Our insurance wouldn't have paid for it, anyway.

Instead we opted (at our own expense) to purchase a meter (a CoaguCheck model identical to the one used in our clinic) from overseas.  We periodically test it against both clinic tests and IV blood draws. Our cardiologist gave us standing instructions in how to adjust the warfarin dose (if needed) - and also clear definitions of when aberrent tests should be immediately rechecked at the office, or if neccessary, at an Urgent Care facility, or worst case, an ER. (That's never been necessary, since being able to test has increased our ability to 'stay in the zone", continuously.)

In addition we are able monitor INR levels whenerver there is a med change (everything seems to monkey around with warfarin!).

Economically it's better since an INR tests cost our insurance (or us during the deductible period) about $30.  The test strips cost $6 ea., so it is more expensive, but the added cost gives us much more information.  We also live about an hour away from the clinic, so much time is saved, too.

My husband tests regularly, and whenever there is a question related to dietary variations, and whenever his Afib starts.

This gives us confidence, peace of mind and a much-needed measure of that elusive thing called "disease mastery".

Some of the comments entered previously and a careful read of the THINRS article illustrate what I believe is often a serious obstacle to realizing the benefits of self testing.  The problem is incomplete communication of information between the patient and the anticoagulation clinician when the INR is reported.  In some situations, the clinician is only alerted if the INR is out of range; and other important patient-specific information is not communicated routinely.  For example, when patients reported their INRs in THINRS, they were instructed to contact their anticoagulation clinician only if their INR was out of range or if they had been hospitalized recently.  As with most other efforts to improve INR control, THINRS achieved only a 3-4% increase in INR time in range with self testing.    In contrast, at least four studies have utilized online reporting systems to improve the thoroughness and efficiency of information communication (1-4).  In these trials, the INR time in range improved by 9% to 23% to time in range values of approximately 70% to 80%.  These studies were too small to evaluate a difference in clinical events, but the degree of INR control (compared to "typical" INR control) was associated with approximately a 50% lower rate of stroke, myocardial infarction, major bleeding, and death in two large atrial fibrillation studies.  Further, the event rates were lower with good INR control than that seen in the patients receiving the comparator drugs ximelagatran and dabigatran(5-6).  Two of the 4 small studies also reported that fewer than 10 minutes of clinician time were required to manage 4 "virtual visits" per patient per month (while also freeing patients from frequent clinic and/or lab visits).

1. Ryan F, Byrne S, O’Shea S (2009) Randomized controlled trial of supervised patient self-testing of warfarin therapy using an Internet-based expert system. Journal of Thrombosis and Haemostasis 7:1284-90
2. Harper PL, Pollock D (2008) Anticoagulation self-management using near patient testing and decision support software provided via an Internet Website improved anticoagulation control in patients on long-term warfarin. Blood (ASH Annual Meeting Abstracts) 2008: 112 (Abstract #1278)
3. Ferrando F, Mira Y, Contreras MT, Aguado C, Aznar JA (2010) Implementation of SintromacWebtm, a new internet-based tool for oral anticoagulation therapy telecontrol: Study on system consistency and patient satisfaction. Thromb and Haemost 103:1091-1101
4. Bussey HI, Walker MB, Bussey-Smith KL, Frei CR. Superior oral anticoagulation management with self testing and automated online management; An interim analysis. In: American Heart Association Meeting on Quality of Care and Outcomes Research in Cardiovascular Disease and Stroke 2010 meeting 2010 (poster # P260 ID#341) Washington, DC, May 21, 2010
5. White HD, Gruber M, Feyzi J, Kaatz S, et al. (2007) Comparison of outcomes among patients randomized to warfarin therapy according to anticoagulant control: results from SPORTIF III and V. Arch Intern Med 167:239-245
6. Wallentin L. www.theheart.org/article/1046957.do accessed last on December 28, 2010