PT INR Home Monitor Patient Testing With inratio (Picture).

If you aren't in the medical field you probably have no idea what I'm talking about, but the idea is  huge and I found myself asking why this technology hasn't become the standard of care?   What's this PT INR testing and monitoring I speak of?  What's inratio and why do I think the time has come for patients to take a more proactive role in their health?

Warfin (generic for Coumadin) is  the pharmacy industry's gift to internists.  Without coumadin, I don't think the hospitalist movement would have gained as much traction as it has.  While coumadin has done a lot of good in this world for folks with thrombotic or thrombo-embolic tendencies, the complications can be horrific.   Coumadin is a life alterting medication in so many ways.  Patients have to avoid certain foods.  They have to be careful about any type of activity that could cause internal hemorrhage and they have to be extra diligent about medication interactions.


Like so many common drugs, warfarin is metabolized through the cytochrome P-450 enzyme system.  That means many drugs will interfere with the metabolism of warfarin and increase or decrease the effectiveness (as measured by the protime (PT) and normalized to the INR (international normalization ratio) of the drug.  Most patients who need anticoagulation are treated to a goal INR of 2.0-3.0, with an INR of 1.0 equivalent to a patient with no warfarin in their system.

To make the situation more complex, everyone will metabolize Coumadin differently.  In recent years, research has indicated we all carry genes that turn us into high or low metabolizers.  There are in fact gene tests, which I could order on you, to tell me if you are a high or low metabolizer, which would tell me whether you would require higher or lower doses than the average Joe.  Unfortunately, by the time this test result would be available, most patients have already found their dose using standard titration methods.

As a hospitalist, I have admitted hundreds of patients over the years with complications directly related to warfarin therapy.  I've witnessed cerebral T waves in a patient with a spontaneous intracranial hemorrhage as well as  massive gastrointestinal bleeding (very common)  for over treatment, in  addition to  pulmonary embolism and stroke from under treatment.  I've seen it all.

The drug is dirt cheap.  It's only  $4 at Walmart.  But diligent monitoring is necessary to maintain therapeutic levels of the drug and prevent catastrophic complications.  Early on, we draw PT and INR levels every day while in the hospital, even on patients who come in on Coumadin.  Acute illness and many antibiotics have a tendency to make INR levels get out of countrol very quickly.


Just imagine, however, that most community bound patients do not have the luxury of daily monitoring and quick dose changes in the hospital.    Most patients would have to go to their physician's office and wait for an hour to get a three minute blood test.  Most patients do not want to deal with that hassle.  Most patients would find daily monitoring intolerable, even given the risks of catastrophic complications.

What's the solution?  Several months ago, a patient showed me his PT INR testing device by inratio that allows for patient home monitoring of protimes and INRs.  I snapped a picture of it.  It works similar to the glucometer diabetics use to check their blood sugar.  Patient's prick their finger and place a drop of blood onto a strip, then place the strip on the device.  

What a great idea.  Patients taking their health into their own hands and verifying that the Bactrim they started or that salad they ate won't put them at  dangerous therapeutic levels of their warfarin.

Then I did a little checking and saw the price of this home PT INR monitoring device on Amazon at nearly a thousand dollars.   The testing strips alone were about $200 for a box of 48.    I was shocked to say the least.  I guess it's not ready for prime time, at least not at these prices.  I don't have any idea if insurance would pay for this equipment if it came with a prescription verifying medical necessity.

Whatever the case may be, I congratulate this patient for taking control of his health and monitoring his own levels.  I wish all patients were like that.  Just one other comment.  After you're done taking control of your health and monitoring your PT INR at home, don't call the doctor asking for a phone consultation on what to do with a value you obtain outside the target range. They won't get paid for this free advice that comes with risk.   For this, you have two options.
  1. Find your answer on Google and adjust your own warfarin dose.  If you need a new prescription dose of your Coumadin, you'll have to make an appointment to get a new prescription.  
  2. Make an appointment to come in.  
These are the only two ways your physician will get paid for work provided.


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