It's been a while since I've been on this site.
One of the things to consider when taking warfarin is consistency. If you drink beer, try to drink a consistent amount daily, if you can. This way, when you test your INR and adjust the dosage to account for any effects that the beer (or greens, or whatever) may have on your INR, you should have a fairly consistent INR because your diet (food, alcohol or ?) hasn't changed.
I agree with Pellicle on many things. I agree that it's hard to trust many anticoagulation clinics. To me, it makes NO sense to schedule repeat testing every month, or two months, or even longer periods. No sense at all.
The fact is, if your INR is too low (usually below 2.0), and stays too low for a continuous period, you may wind up with a stroke in less than a week. If it's too low for just a day, you're probably okay. So, even if an occasional beer or salad orgy brings your INR down for a day or so, you're probably OK.
BUT - back to the discussion about delays between testing. If you can develop a clot in just a week or so when your INR is too low, does it make any sense for a clinic to ask you to retest in a month? They assume that your activities are consistent, and if not, they have no way of assessing if you're at risk. This is good for the clinics - if you die, or stroke out, or bleed out, you stop going to the clinic - to them, you've just dropped out of the program. This is great for their statistics - 'patient dropped out of program' - not 'patient died because they followed our advice.'
Some clinics have adopted this 'once a month' or 'once every two months' protocol because when these protocols were written, patients had to travel to labs for a blood draw. It was inconvenient and probably somewhat expensive.
In these days of readily available home testing, there's really no reason why weekly tests shouldn't be done - even if your INR is consistent from week to week. In my own personal experience when managing my INR, I've had occasions when my INR dropped below 2 -- I retested, I increased my dose by 1/2 for one day, and tested on the next day. If my INR remained low -- and a monthly blood draw may not have shown this - I may not be writing this now.
A few years ago, I was doing parallel tests - sometimes daily - using three meters and a monthly blood draw for validation. The meters that I tested were the CoaguChek XS, the InRatio 2, and the Coag-Sense. I occasionally also tested with the Protime 3 and 5 channel cuvettes (strips).
In almost every case, the Coag-Sense reported slightly lower than the lab, and slightly lower than InRatio and CoaguChek XS.
The InRatio was unreliable and I abandoned that meter, even though I had a year's supply of strips.
The CoaguChek XS usually reported higher results than the lab and was almost always higher than the Coag-Sense.
For my own safety, I prefer a meter that gives a result that is equal to or lower than the lab. For example, if my Coag-Sense gives me a 2.0, I can be reasonably certain that the lab will show 2.2 or higher - still a bit low, but still out of danger range.
By contrast, a meter that reports at or higher than lab values is less satisfactory to me. If my CoaguChek XS gives me a 2.2, I may feel somewhat safe - until I consider that the lab value may be closer to 1.9 or so.
For myself, I prefer the Coag-Sense over any other meter. This meter is not very well known, unfortunately. The company now has a collection tube (a capillary tube) that makes it easy to get the drop of blood into the tube and transfer it to the strip. The meter is larger than the CoaguChek XS, but strips are somewhat less expensive, and I trust this meter to be more accurate, overall, than the other meters.
(BTW - I wound up with three of these meters, but only need one, or perhaps a second for backup).
I'm not trying to sell anything. I don't work for Coagusense. My goal is to help others make the right anticoagulation decisions. When I have a LOT of money, I'd eventually like to help those who can't afford regular testing to be able to get the testing at little or no cost.
I went for three years without testing before I realized how dangerous this REALLY was. I was taking a dose that apparently worked for me - but I was AWFULLY DAMNED LUCKY that I didn't kill myself by NOT testing.
Get a meter. Compare the results to a monthly blood draw. Learn the difference between meter and lab and adjust for this. Test weekly, if possible, and more often if your INR is too low, so that you can see if it comes back into range.
