I've seen a few papers, and references to other papers, that say that self testers are in range more consistently than patients who don't self test. I think that the reality is that self testers are in range even more consistently than the studies report.
And I think that the most poorly run anticoagulation clinics, using the most outdated protocols as they relate to frequency of testing probably have the BEST rate of patients whose INRs are within range.
Here's why:
Anticoagulation clinics schedule repeat testing. If a patient's INR is 'consistent' or 'consistently in range,' these clinics often switch frequency of testing from twice month to monthly, to every other month, and sometimes to EVERY THREE MONTHS. The assumptions are that 1) if a patient's INR has been consistently in range the past few tests, nothing will change between testing, 2) if the patients INR is going to be stable between tests, it will save money to not have to repeat an unnecessary test 3) these overworked clinics have more important things to do than to counsel patients whose INRs are always in range and 4) if a patient doesn't return, the patient must have gone to another clinic, so he or she is removed from the database for non-compliance or because he or she 'dropped out' of the program. No follow-up on the patient's status is performed - he or she is just removed from the list of active patients.
What they seem to overlook is that 1) it only takes a week or so for a person with an INR below 2.0 to form and throw a clot (and possibly die), 2) although possibly not as likely, the damage from too HIGH an INR could be potentially life threatening and may not take very long to exhibit symptoms, and 3) if a person with either situation exhibits the symptoms (and doesn't die), the person will probably switch clinics or be unable to continue as an outpatient. There are many factors that can cause a person's INR to change rapidly. Diet is one, the use of antibiotics is another, even certain 'organic' supplements can cause changes in INR. Although these clinics are aware of this, they still seem, illogically, to be happy with monthly or even less frequent testing.
I'm a strong advocate for weekly self testing, although I don't always test this frequently. It's the only way to know, week to week, that my INR is in a safe range.
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As far as 'used' meters are concerned, I don't think that I'd usually worry about the meter's lifespan. The CoaguChek XS is designed for use in doctor's offices, and also for self-testers. So are the others. These meters are designed with a lifespan of hundreds of tests.
Even if you test weekly, the number of tests you'll run in three years may still be fewer than the number of tests run in a clinic or doctor's office in a few days or weeks.
Many of the used meters probably had minimal use. Some meters may come from people who had them, but died of old age or other issues (and the heirs have no use for them, so they offer them for sale). Some may be medical 'surplus' - coming from clinics, doctor's offices, or hospitals that have replaced them with the same meter (but can no longer deduct the cost of the 'old' meter from its taxes) and sold them to re-marketers.
I've acquired most of my meters used -- I only got one direct from the manufacturer, but only because I implicated this manufacturer's defective meter as causing a TIA because of inaccurate test results.
If you buy a meter, it's good to ask for a right to return the meter (fifteen days or so), if it doesn't work. It's good to check the meter's results against a blood test. Realize that the meter and the blood draw will probably not agree - that's just the nature of the testing method. And, if you know someone with the same meter, perhaps comparing your results to the other meter would be of value.
Self-test. It could save your life...
