question about different results

[SHEEPDOG]

Ok, I haven't posted for a while but I just (last week)(thurs) got my INRatio machine. I figured it out without the QAS nurse training and had a result that was just right. 2.2. I was due to go to my cardios office the next monday as it had been a month since I had my INR checked. Their COAGUCHECK came up with a 2.9. This was called into the RN. Just before she called me back, I used my machine and got 2.4. This was a mere 4 (or so) hours after the 2.9 reading. SO WHICH DO I GO BY??? The point of home testing is to avoid the DR office or lab. I don't know WHAT a lab would come up with. If I had just gone with my machine, I would have stayed over my 2.5 max and never known it. If you "DOSE THE DIET" you must have accurate numbers. I am 90%sure there was no USER ERROR. Should I try to get a coagucheck? HELP!

 

[ALCapshaw2]

You've got to realize that there is a 'margin of error' with ANY Test and ANY Instrument.

INR is a Much Improved method of managing anti-coagulation (versus measuring clotting time where reagent variations also enter into the final number), BUT it is NOT as PRECISE a measurement as everyone would like. That's why Doctors prescribe a Range and not a single number, to accomodate those variations.

It would be nice if 'someone' would come up with a way to quantify the test-to-test variation of each instrument and instrument-to-instrument variation (don't forget instrument-to-lab test variation also), BUT, it hasn't happened yet and is not likely to happen anytime soon.

Bottom Line: The Accuracy / Finger Stick - Lab Draw arguments aren't likely to go away any time soon either.

Welcome to the Real World!

 

[Ross]

There can be up to a .6 variance between readings. INR is not a set number, but I think you know that. I'd personally believe my own machine. You'd have to test right there along with theirs to see what you got even remotely accurately. Even a few minutes difference can be a INR difference. Back to back testing even. Better question, do you have yours set to show INR and PT? If so, what PT did you get and what PT did they get?

Just to give you an idea, during my recent surgery, I tested before leaving my house and got 2.2 and 21.8 seonds. The hospitals lab got 2.2 and 21.6 seconds.

Now if I go to my lab at the med clinic, I can take my machine with me and I'll get say 2.8 and they'll get 3.3. I trust my machine more then I do a lab. When you compare one machine against another, your not comparing apples to apples. Different reagents will give different results. If you both used the same test strip and got that, then I'd wonder, well no I wouldn't, because there was a time lapse of 4 hours. If your between 2.0 and 4.0 don't freak out about it.

 

[Jkm7]

Just curious and doubt it made a difference but is there a reason you don't want the nurse training? Is there some chance (s)he might give some little tip that might be helpful for you at some point?


Congratulations on getting your machine. It must feel so liberating.

Good luck.

 

[Bina]

Sheepdog, you are just fine!
Using my Coaguchek I aim to keep my INR at around 3.0 that way even with a variance of .2 the results are still perfectly in range.
It's no big deal at all.

 

[Marty]

Trust your INRatio and it will take good care of you. You will go crazy checking it against the central labs and even other home monitors. You may wish every now and then to use a "control"( a person who is not on ACT) and see if you get 1.0-1.2.If you do, your monitor is fine.

 

[bvdr]

Trust your INRatio and it will take good care of you. You will go crazy checking it against the central labs and even other home monitors. You may wish every now and then to use a "control"( a person who is not on ACT) and see if you get 1.0-1.2.If you do, your monitor is fine.

Ditto! I trust my Protime machine and if a result is different than a lab then I go with what I tested on my own machine. Every now and then I'll do a stick on my husband and he is always right about the 1.0. I would drive myself crazy if I fretted about the varying results. It would be lovely but it just doesn't happen.

 

[netmiff]

hear, hear! I echo all of the above. You seem to be worrying about minor variances.

" . . . I would have stayed over my 2.5 max and never known it."

Most of us here have a range of either between 2.0 and 3.0 or 2.5 and 3.5, given by our doctors. However, most of us don't freak (at least I don't) until I get about 2 readings that are above 4.5 or so. If it is lower than 2.5, I tweak the dose so it goes up for next time.

Bottom line : trust your machine; you will get more comfortable with it, the longer you do it and more comfortable with being slightly higher than your range.

Others will be able to explain it better than I can, I am still half asleep and not thinking straight, just wanted to say dont worry about minor variances.

 

[Cris N]

Back when I was going to a Coumadin clinic the nurse and I were curious about test results. She was using a Coaguchek S and did, if I remember, 4 tests within about 10 minutes. While I don't remember the results I can tell you that there was a noticable difference between the tests. Something like .8 difference between high & low.

I home test now and trust my machine but I also like to stay at the top of my range... gives me a better margin for error.

 

[SHEEPDOG]

Thanks...

Thanks...

...for all the help guys. I knew I could get some well educated answers here. Guess I was just a bit unclear about minor differences. I am not really freaked out but any concern I had has been eliminated. Thanks again.