Sooo frustrated.

[catwoman]

I have had 2 lab draws recently within a short time after or before testing with my INRatio. The first was early on Friday, June 7, and my INR was 3.4. Had a colonoscopy and late that afternoon was at an ER with appendicitis. My INR on a lab draw was 3.4 before they started reversing anticoagulation with vitamin K & FFP.

The morning of Tuesday, June 18, my INR was 2.9 on a lab draw and when I got home about 3 p.m., it was 2.9 on my INR.

Those tests were not immediately back to back, but they were close enough to make me feel comfortable with my INRatio. When I have tested against the CoaguChek in my family doctor's practice, it was only 0.1 different.

 

[Protimenow]

I had some issues a few months ago, with the InRatio 2 being much higher than the lab blood draws. I called Alere. Their answer (and I don't know if I'll ever forget it) was: "trust the lab.' If you call them, they'll probably go through the testing procedures to see that you're not making any errors. In most cases, my InRatio reports .3 - 1.5 higher than the labs.

As others have stated, the labs aren't always 100% trustworthy, either. (I had two blood draws, with results from two different labs, a few months ago, and the results were surprisingly considerably different).

Talk to Alere. They may have some suggestions. They may try another batch of strips. They may even exchange the meter so they can check the current one to see what, if anything, is wrong with it.

 

[chaconne]

So far I've had good results comparing the InRatio2 with a lab draw. For the 4 comparisons I've been able to do so far, the InRatio2 was +0.1, -0.2, -0.2 and 0.0 off from the lab. All these measurements were in range from 2.5 to 3.1.

 

[Protimenow]

That's good to hear. Perhaps the bigger variations occur when the INR heads to 3.5 and higher.

 

[marc_kowal]

Had a lab draw yesterday at my usual spot and then did a finger stick 30 mins. later with my InRatio2. Here are the results;

Lab Draw- 2.9
Inratio2- 3.6

That's a .7 variance. I'll be calling Alere later to see what they want to do next. I did a finger stick with my wife and it came back at 0.9. So who knows what's going on.

 

[dick0236]

Had a lab draw yesterday at my usual spot and then did a finger stick 30 mins. later with my InRatio2. Here are the results;

Lab Draw- 2.9
Inratio2- 3.6

That's a .7 variance. I'll be calling Alere later to see what they want to do next. I did a finger stick with my wife and it came back at 0.9. So who knows what's going on.

Your test on your wife(.9 INR) seems to indicate that your meter is reading accurately. Is the lab sample a vein draw and do you have it drawn at the lab or is it drawn in your docs office and sent out to a local lab?.... If so, it does not surprise me that a .7 variance could occur......due to the time delay in sample testing. I had a vein draw that was sent out to a lab of 4.7, a finger stick at my docs office of 4.5, and a home test, one hour before doc office stick of 4.0 a few months ago. It only prooved that I was above my range (2.5-3.5) and I needed a slight correction. Due to the reagent differences and time between testing at home and in office, and the signicant time delays in sending out to lab, the variances don't surprise me.

Once I began home testing, I had to learn to trust my test. I go to my doc for a monthly finger stick (his insistence), even tho I test weekly at home. My results and the office results are normally within +/- .2 and as long as they stay in that range I am comfortable.

 

[Protimenow]

In my experience, the InRatio has always been higher than the lab. This forum has even had some mathematical algorithms for converting the InRatio results to lab results. A difference of .7 doesn't surprise me.

Dick's point regarding issues with labs -- whether the blood has been stored before testing, etc., is an interesting one -- I've seen where some clinics that hold the blood until it's picked up by a lab and tested (presumably that night or the next morning) are considerably different from testing with a meter or at other facilities that test within hours of the actual blood draw.

If your finger stick values are within +/- .2 of your doctor, this isn't surprising -- especially if your doc is using the same type of meter. BOTH meters would probably have the same amount of deviation from the lab results.

(Call Alere. I'd be interested if they didn't say what they told me -- "Trust the lab.")

 

[marc_kowal]

The thing that concerns me is that in the past when I checked my reading vs the lab, the InRatio2 was always .2-.5 higher then the lab. Now I get readings that are .7 and .9 higher then the lab. So I could be thinking that I'm in range when I may be really low.

 

[Protimenow]

If the INR that is reported on your meter gets close to 2.0, I would also be concerned. Blind trust of my meter's accuracy was not healthy for me.

You will probably find that the difference between the meter and the lab will widen as the INR goes up. If you're recording the results of lab draws and your meter's results, you may see that this applies in your case.

For me, my main concern is to be certain that my ACTUAL INR is above 2.0 -- I'm not even troubled by INRs as high as 4.0 if these 'high' INRs come from an InRatio or CoaguChek XS.

 

[marc_kowal]

So I just spoke to Alere and they said that the acceptable variance between a lab draw and a home testing unit as established by the WHO (World Health Organization) is 30% of the lab result. So even though some of my number were .7 and .9 off, the rep. said that it was close enough to warrant changing the meter (at their cost). So I should be contacted by Alere Home Monitoring tomorrow and get the ball rolling on a new meter. Once I have the new meter, they want me to run some more comparison tests.

 

[marc_kowal]

So I finally received my replacement meter last week. I went to the lab on Weds. to have a blood draw and then went into the parking lot to use the new meter. I got a 4.6 and that seemed odd since I was hovering around a 3.2 for the last 3 weeks. Went back to my office and tested again, this time I got a 5.0. We had eaten out the 3 previous nights, so I figured I may have under estimated some "K" values in my meals. I got my lab results back the next day and the lab (which I trust) had me at a 3.6! My technique is good and I'm following the instructions to a "t", so it can't be user error. I'm at the point now where I may stop using the InRatio2 and look at a different meter. This is just making my head spin.

 

[dick0236]

........ I'm at the point now where I may stop using the InRatio2 and look at a different meter. This is just making my head spin.

I check at home weekly using the INRatio2 and monthly at my docs office using CoaguchekXS. We seldom agree and are usually within +/- .3. I seldom get lab draws and the last one was in Jan., 2013. I got 4.0, my doc got 4.5 and the lab got 4.7. Before you junk the meter......stick your significant other or a friend...you should get an INR reading of about 1.0. If it's close to 1 your meter is reading correctly and you need to look further into your discrepancies.

 

[pellicle]

Marc
Do you recal a conversation which you Pem and I had some time ago about his inRatio and results?

He said something along the lines of:

formula that allows me to predict almost perfectly what the lab result will be based on what the home meter result is. That formula, in case it is useful to someone else, is to take the meter result, raise it to the power of 0.85 (use a scientific calculator - the windows calculator has a scientific mode with X^Y as a function). The "Adjusted Home" line on the graph is based on this formula.

Applying this to your reported result above nearly perfectly matches the lab result

4.6[SUP]0.85[/SUP] = 3.6588

PS I just referenced some reports by protimenow who wrote

Lab: 2.52
Coag-Sense 2.2 (and, shortly later, 2.1)
CoaguChek XS 2.7
InRatio 2 3.0

3[SUP]0.85[/SUP] = 2.54

Quite close to his reported lab result.

 

[Protimenow]

Pem's formula does seem to be pretty good at predicting some lab results. My InRatio (and InRatio 2) seem to have ALWAYS been higher than some of the other meters, although at times it has come pretty close to the CoaguChek XS. The difference that you've gotten when you went from parking lot to office is a bit of a concern -- but this is an InRatio 2, isn't it?

I EXPECT that my InRatio 2 values will be high. Although I have probably 60 or more InRatio strips, I rarely test with that meter.

I have more confidence in the CoaguChek XS (which seems to be just a bit higher than the labs and my Coag-Sense meter), and in the Coag-Sense meter (which seems to always to be somewhat lower than the CoaguChek XS). Lab results, when I get blood drawn, is usually somewhere around midway between the Coag-Sense and the CoaguChek XS.

It CAN be frustrating. There doesn't seem to be any ALWAYS accurate tester. I usually trust the hospital lab more than my meters. I trust the CoaguChek XS to be a bit high, and the Coagu-Sense to be a bit low, but as long as the Coagu-Sense gives me close to 2.5, and the CoaguChekXS doesn't give me a 4 or higher, I'm feeling comfortable to be in range.

In the case of the InRatio 2, I would personally be rather pleased with reported INRs of about 2.9-4.2 or so.

 

[pellicle]

Hi

Pem's formula does seem to be pretty good at predicting some lab results.

Seems poor to me that it needs such a straight forward correction. It makes me wonder about the design, and if they are taking other factors into account and attempting to make a one size fits all within e bounds of their process.

I have more confidence in the CoaguChek XS (which seems to be just a bit higher than the labs and my Coag-Sense meter), and in the Coag-Sense meter (which seems to always to be somewhat lower than the CoaguChek XS). Lab results, when I get blood drawn, is usually somewhere around midway between the Coag-Sense and the CoaguChek XS.

Marc, is it possible to get your cover to let you try a different meter? As dick and (increasingly) protimenow many others have reported they are happy with theirs (add me to that list) it could be that for you the coaguchek XS gives a more consistent to lab results.

 

[Protimenow]

Pellicle:
I'm in full agreement with your question about the InRatio. It sort of amazes me, too, that if such an easy calculation that will bring the results of an InRatio test into a very close match to lab tests, that such an automatic correction wasn't built into the meter in the first place. I don't use my InRatio as much as I used to (and I mistakenly relied on it in the past, just before my TIA), but it would be interesting to compare a lot of tests using the InRatio to blood draws. IF the adjusted values are very close to the labs, then it would be reasonable to argue for doing the testing with the InRatio, but then applying that algorithm in order to get the REAL value. Otherwise, the InRatio is just a meter that is always higher than the labs.


Marc -- I hate to argue against a particular meter, but I agree with Pellicle -- I think that you will get results that are closer to lab results if you use a CoaguChek XS instead of an InRatio. In addition, it's easier to get that drop of blood onto a CoaguChek XS strip than it is to get it onto the dot on the InRatio strip. (FWIW -- I also appreciate my Coag-Sense meter - it may be a bit lower than the labs, but I trust it to help me assure myself that my INR is not BELOW range.

 

[pellicle]

Hi

it would be interesting to compare a lot of tests using the InRatio to blood draws. IF the adjusted values are very close to the labs, then it would be reasonable to argue for doing the testing with the InRatio, but then applying that algorithm in order to get the REAL value.

well if you have some other older records in your notes you could perhaps run a few calculations and see how it went for you.

 

[Protimenow]

Yes. I thought about that. Unfortunately, I don't have a lot of blood draws for comparison.

 

[marc_kowal]

Did another comparison test this past weds.

Lab Draw- 3.4
InRatio2- 3.8

Based on Pem's formula, I should have seen a number around 3.11 from the lab. I'm also going to run Pem's formula against my past comparison numbers and see how close they were. I still need to contact my insurance to see if they will allow me to test a different meter.

 

[dick0236]

Lab Draw- 3.4
InRatio2- 3.8
.

The difference in PT(clotting time in seconds) between 3.4(33 sec.) and 38(37sec.) is 4 seconds. It is accepted that different reagents and instrumentation systems can, and do, produce differences in INR. If your range is 2-3, you are above range and probably should make a small dosing change. If your range is 2.5-3.5...eat a green leafy salad, or two. The problem with using different testing methods is "which one is right??"....flip a coin. Try to micro-manage INR and you will go nuts.