I haven't gotten tired of sticking my fingers to run tests. I still have some fingers that do okay after being punctured once or twice a week.
My quest for a reliable, accurate meter may always continue.
However -- I'm realizing that some of the variance from meter to meter, or from test to test (even in the labs) may be as closely related to the accurate identification of the reagent used (this is a material that starts the blood clotting, and that is used to provide a factor that is divided into the clotting time in order to calculate an INR) as it is to the testing method itself. In theory, if the SAME reagent was used in the lab as the one in the strips, the result from meters and lab would all be the same.
However, from what's been posted on this site and elsewhere, there is no ABSOLUTELY accurate way to calculate a reagent's exact value. Without this knowledge, ANY testing can be considered, in some ways, to be something of a guess. I'm sure that the companies that provide the reagents to the labs, and the makers of the strips, use every method possible to determine an exact value for their reagents - but this may not be possible.
Given this background information - and the knowledge that it may not be possible to get an 'accurate' INR using any method, I've re-evaluated some of my criteria in a search for the meter that I trust the most.
Also, noting that my personal goal is focused more on staying above my minimum INR (for me, I'm most comfortable above 2.3 or 2.4 on the Coag-Sense meter) than it is to stay below the maximum (I am less uncomfortable with an INR of 4.0 than I am with an INR of 2.0), I've narrowed my selection to a single meter.
Before I get to my choice, a few things:
I found that the InRatio is ALWAYS high. My absolute trust in this meter's accuracy may have contributed to a TIA that I had 17 months ago. Although this meter is probably fine for many self-testers, it should be noted that the meter seems to always give results that are higher than lab results, and you should probably not be satisfied with an INR that is near the bottom of your range. Although I have at least a years' worth of strips, I no longer use the InRatio, except when I have some strange results on my other meters.
The ProTime meter is a bit more of a pain to work with than the others. It takes more blood, the strips require refrigeration, and a recent lot of cuvettes was recalled. The five channel cuvettes that replaced the bad three channel cuvettes are in my refrigerator, and will probably stay there, mostly unused, until they expire.
Hemochron is a meter that is used in anticoagulation labs and is reportedly even used in Operating Rooms to monitor various blood factors. I have one, but need a data cable so that I can set it up. HOWEVER - it IS a medical device designed for use in hospitals and operating rooms. If it fails quality control tests, it's probably a brick that I can do nothing with. It's not a viable alternative to the other meters.
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That said, my choice came down to two meters -- the CoaguChek XS and the Coag-Sense.
In my testing, the two were rarely in complete agreement (although there WAS one test where they were extremely close). In my testing, the Coag-Sense results were always lower than the ones from the CoaguChek XS.
When compared to lab results, the lab values have been close to midway between the Coag-Sense and the CoaguChek XS.
If I was only able to choose one meter -- fanfare please -- it would be the Coag-Sense.
Here are my reasons:
Because I would rather know that my INR is ABOVE the minimum for my range, I would choose the Coag-Sense because it reports lower than the CoaguChek XS and a value from this meter would almost assure me that my INR is NOT TOO LOW.
The testing method is pretty interesting -- the blood mixes with the reagent, and the mixture goes below a wheel that is spinning through the blood. An optical sensor detects when the blood has clotted (the wheel stops spinning), and can provide an exact prothrombin time. If the reagent is accurate (and you should assume that it is), the INR is reported by the meter -- and this should be pretty accurate.
By contrast, the CoaguChek XS measures impedance, an electrical property that changes as blood clots. It's a less direct method than the one used by the Coag-Sense meter. If I was more concerned that my INR doesn't get TOO high, I may choose the CoaguChek XS. (However, I was told by Coag-Sense that there are clinics that use the Coag-Sense as a second check if the INR reported using other meters is at 4 or above).
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I will probably continue testing with Coag-Sense and CoaguChek XS -- possibly until I run out of the CoaguChek XS strips -- and certainly any time I get a blood draw. Once I run out of XS strips, the Coag-Sense may be the only meter that I regularly use.
(One other thing -- I have a 'new' (used once to compare to my 'work' meter) Coag-Sense meter. I don't need two Coag-Sense meters and may be interested in selling it. My conclusion about which meter to trust has NOTHING to do with the availability of this extra meter -- I have two InRatio meters, and a few ProTime meters, and haven't chosen either one as my most trusted meter, but I may be willing to get rid of one or more of these meters, too)