Atrial fibrillation patients are constantly at risk from blood clotting, strokes, or both. As a result, if you have atrial fibrillation there is a good chance that you’re either taking blood thinners now, or that you will be taking blood thinners someday.
Most people will be working with the drug Warfarin, also known as the brand name Coumadin. Warfarin is a time-tested drug, but it comes with some challenges.
The biggest challenge of Warfarin is that you will have to monitor your blood. You do this through the PT-INR test (also known simply as the INR test).
What is the PT-INR Test?
PT is the abbreviation for “prothrombin time.” Prothrombin time is just a measure of how quickly your blood clots.
INR is an abbreviation for “International Normalized Ratio.” This is the unit of measure that’s used to determine how quickly your blood is clotting.
So when you take the INR test, the doctor or the nurse will simply come and draw your blood. Then they’ll send your blood to a lab where they’ll add a blood clotting agent to your sample. They’ll then test the time that it takes for that blood to clot.
There are also INR self-tests that you can take at home. You stick your finger, put the blood on a test strip, run the strip through the machine, and get your result.
Low numbers are good — 1 is the baseline for a perfectly healthy patient who is not on blood thinners of any kind. Higher numbers – 5 or higher – are dangerous.
When your tests come back your doctor will help you make adjustments to your lifestyle and medication so that your INR stays within an optimal range.
How Often Should You Take an INR Test?
That depends. Some people only have to take the test once a month. Some have to take a test every week.
Usually weekly tests happen when you first start the therapy. This allows the doctor to adjust your medication. Once the doctor is satisfied he’ll typically move you to testing every four weeks.
This is in part because the most trouble you’ll typically have stabilizing your INR levels will be at the very start of the therapy. Ranges can be all over the place at first, ranging from high to low and back again, but it usually stabilizes over time.
What You Should Know about Self-Testing
Self-testing can be very beneficial. Just look at what ClotCare.com has to say about it:
“In recent years, several studies have demonstrated that patient self testing leads to better care for patients on Warfarin. In 2011, the results of 22 such studies that included more than 8,000 patients found that self testing patients had a 42% lower risk of new blood clots, a 12% lower risk of major bleeding, and a 26% lower risk of death.”
These benefits are the result of better INR control.
Self-testing also makes your life more convenient. It makes it easier for you to travel, reduces time away from your other commitments, and puts some power back in your hands. For example, you may be able to learn how to adjust your own dosages instead of having to consult with a physician every time.
However, you should know that it can be expensive unless your insurance plan covers it. And you do need a prescription for self-test devices…you can’t just pop into the drug store and buy one. Doctors will also generally want you to receive some training on the machine before they write that prescription.
You should also know that most doctors won’t prescribe self-tests to you unless you’ve been a good, compliant patient in the past. So if you want this option, follow your doctor’s orders!
Once you have the prescription you can buy your self-test machine. Here is a list of the major manufacturers.
Of course, if you’re not comfortable self-testing there is nothing wrong with continuing to take your tests at the clinic or at your doctor’s office! You should make the decision based upon what you feel will be best for your life and health.