Possible Coagxs strip problem

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dick0236

Eat the elephant one bite at a time
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I just received a registered letter from my coaguchek supplier. Some strips from a number of lots have given some bad INR numbers. If you have had INR readings above 4.5 with any strips from any of the affected lots you need to get a confirming INR from a different source. Apparently this is not a recall. I am currently using strips from one of the listed lots but have not had an INR reading above 3.8 and Coaguchek tells me I can continue using these strips until I get my next automatic shipment early in October. I am not computer savvy enough to attach the letter I received but they give the following 800 number if I had any questions....800-428-4674......or I suppose you could call Roche directly. More than likely those of us using an INR service are being notified.......but maybe not for those of you buying strips on ebay, etc. This doesn't sound like a problem unless you are getting readings above 4.5 and I am not trying to alarm anyone.....this is FYI only.
 
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Warrick

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New Zealand
I’’ll google it but is there a site where you can find the lots numbers? I’ve just bought 48 strips.
 

pellicle

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Further to Warrwicks detective work, reading the document it makes the following points (bold mine):
Roche Diagnostics has received an increased number of complaints regarding deviations of CoaguChek test strips against non-Roche controls as well as laboratory methods during the last weeks. Therefore, we initiated an in-depth analysis in order to determine the reasons for the observed differences.
Our findings:
For values within the common therapeutic ranges (up to 4.5 INR) and covered by the new (rTF/16) WHO standard (1.5-4.5 INR) a bias of 6% was verified when we compared the new CoaguChek test strips against Innovin-based thromboplastin from the previous (rTF/09) reference WHO standard. This bias is caused by the differences between the previous (rTF/09) and the new (rTF/16) WHO reference standards and was expected to be seen.

For values >4.5 INR an unexpected increasing positive bias was found between CoaguChek test strips referenced to the latest WHO rTF/16 and Innovin-based laboratory methods referenced to rTF/09.

No deviations have been experienced with the previous CoaguChek test strips referenced to the previous WHO standard rTF/09. Most laboratory methods are still calibrated against the previous (rTF/09) WHO standard.


So basically if you're "in range" then perhaps (if you are one of the listed lot numbers) then if you read 2.7 you were probably 2.6 ... stuff like that

The lot numbers for convenience:

CoaguChek XS PT Test REF 04625374190, 04625358019, 04625315019

Lot numbers from 272167 up to 334498

I recommend you read the document

Below is my current bottle of strips for reference and where I understand the reference and lot numbers are found:
 

pellicle

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lastly, this is why I always say this INR measurement is not like measuring a piece of steel ... its by definition "rubbery"

So you should NOT attempt to sit on edge INR cases, this is why you target the middle of the range (and why modern thinking is to give the patient a TARGET INR

If you are up for it I strongly suggest you read the following link

http://www.practical-haemostasis.com/Miscellaneous/Miscellaneous Tests/isi_and_inr.html

this is a good summary point below (again my bold):
[h=3]Introduction[/h]
The Prothrombin Time (PT) in an individual with one or more deficiencies of a clotting factor will vary with the type of thromboplastin (e.g. rabbit, human, bovine etc) used in the assay. This difference in sensitivities is known as the sensitivity index. Individual thromboplastins can be calibrated against an international WHO reference thromboplastin (International Reference Preparation or IRP) to assign them an International sensitivity index or ISI. The first WHO reference thromboplastin was assigned an ISI of 1.0 and it is against this (and subsequent reference preparations) that all other thromboplastins are calibrated.

so keep this in mind when reading the Roche pdf referenced above (and remember, its aimed at health professionals or people who have a grasp of the chemistry)

Best Wishes
 

leadville

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Wigan, England
Thanks great info, just checked mine and they are not on the list,

Target INR makes lots of sense, i've started to plot my readings using a phone app after taking the advice on this site, it's easier to read in a graph and its very useful for reference.

Thanks again
 

sassyspy

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Apr 25, 2013
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Location
seattle
Thanks very much, dick, all mine are in the target range of numbers as well. Not a peep from the doctors or my "INR monitoring center". I always found them rather worthless anyway, just a call center is all it is.
If mine goes above 5, then I'll go to the lab just so I feel better.

what about the people who dont belong to this forum? I would have never known if not for you. I think it's awful , really puts a lot of people at risk, with Vitamin k being the common response to high INRs.

thank you so much!
 

Warrick

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New Zealand
Hot off the press from my hospital lab as I’m here right now(INR tested 2.4),
they have decided that any INR above 3.0 will be checked with a blood draw due to the possible inaccuracies.
Obviously this is not the official policy from Roche but it will be a country wide policy for NZ.
They said there are not going to be any recalibrated strips available until November.
 

pellicle

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well, I had a conversation with Roche Australia today.

I spoke with the Product Technical Support team and found that the summary and conclusions I wrote above are pretty much exactly a match with their views. I guess in summary they said:
  • because this an outcome of implementing the new WHO standard it is not a "fault"
  • results between the two different WHO ISI standards will result in no clinically significant difference between the previous and the current standard
  • they recommend that if you obtain a reading of INR > 4 that you consult with your physician as soon as possible (normally my guy asks me what I reckon... so I've stopped asking him questions which I know are out of his depth)
  • they are re-calibrating back to the older ISI standard
  • they confirmed that the letter they were sending out was the same a the letter referenced above (that Warrick referenced) except contry specific details were changed.
So none of that was any different to what was found in the letter (and that my understanding was correct)

This raises the point (again) that INR is not only a rubbery thing, but that even the WHO can make changes to re-baseline what INR results actually mean (in terms of the chemical assessment of how clotting happens and how to time that). So this underscores my view that its much better to sit in the middle of a range (or consider a TARGET INR) than to say "I'm good, I'm inside the boundaries"

Best wishes
 

RobThatsMe

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I got the letter too, and the return mailer, but no questionnaire to fill out.
They also include a LIST of the lot numbers effected.
I am not able to post pictures, perhaps someone can post a copy of the Effected Lots.
 

pellicle

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Rob
RobThatsMe;n885271 said:
I am not able to post pictures, perhaps someone can post a copy of the Effected Lots.
if you open that PDF that Warrick liinked to you'll see the lot numbers in there (as well as diagrams on how to see what lot your strips are from, which is what I also put into a picture above). As well I put the lot numbers again in my post above:
http://www.valvereplacement.org/forums/forum/anti-coagulation/885238-possible-coagxs-strip-problem?p=885247#post885247

Best Wishes
 

LondonAndy

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Aug 1, 2015
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London, UK
Thanks Dick, Warwick and Pellicle as always. So the bottom line is that even if we have test strips from the affected batches this is not a biggie, and I bet those of us self-testing regularly are still much better informed as to our current INR than those who have to rely on clinics. Now back to work peeps xx
 

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