Coaguchek INRange ...

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pekster11

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I have a Coaguchek INRange meter too:

I have compared my results with the INRange meter, with the lab results (venous draw). Both tests taken within a couple of hours:
INRange result has never been >0.3 higher than the lab result so far:

17th June INRange: 5.8 Lab venous draw: 5.6
22nd June INRange: 2.8 Lab venous draw: 2.5
1st July INRange: 2.7 Lab venous draw: 2.7
12th July INRange: 2.4 Lab venous draw: 2.2

Will be doing another comparison on 18th August
 
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bece13

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I agree with you Pellicle, but it looks like there isn't too much else that I can do.

Thanks Pekster, good to know that it works for you. I guess that they are not using Coaguchek at the Lab with venous draw.
 

MdaPA

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but it looks like there isn't too much else that I can do.
Did you review the limitations on the insert that comes with the strips to see if any might apply to you?

Notably re: the XS:
  • The CoaguChek XS System for patient self‐testing should not be used for patients being treated with any direct thrombin inhibitors, including Hirudin, Lepirudin, Bivalirudin and Argatroban.
  • Hematocrit ranges between 25‐55 % do not significantly affect results.
  • Testing has confirmed that PT/INR test results are not affected by:
    • Ascorbic Acid up to 30 mg/L
    • Bilirubin up to 30 mg/dL
    • Lipemic samples containing up to 500 mg/dL of triglycerides
    • Hemolysis up to 1000 mg/dL
    • Clopidogrel (Plavix®) up to 20 mg/dL
    • Fondaparinux (Arixtra®) up to 5 mg/L
    • Heparin concentrations up to 0.8 U/mL
    • Low molecular weight heparins (LMWH) up to 2 IU anti‐factor Xa activity/mL
  • INR results from patients treated with Direct Oral Anticoagulants (DOACs) e.g. rivaroxaban, apixaban, edoxaban, betrixaban and dabigatran may be influenced and should be confirmed with an alternative laboratory method.
  • Samples from patients treated with the following drugs must not be tested with the system: protamine sulfate, oritavancin, calcium dobesilate.
  • The presence of anti‐phospholipid antibodies (APAs) such as Lupus antibodies (LA) can potentially lead to prolonged clotting times, i.e., they may cause false‐high INR values. If you have or suspect that you have APAs, contact your doctor and do not continue INR testing with this device.
See complete list here:
CoaguChek XS PT Test Package Insert for Patient Self-Testing
 

brijeshb

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What I have found while comparing INR lab tests and my coaguchek is when ever lab results are between 2.3 and 2.6 coaguchek will show around 2.8 . As and when the INR increases the gap between lab results and coaguchek also widens . Say for eg when the lab results show 2.8 or 3.0 coaguchek will show 3.7 or 3.9 . So I guess the accuracy is not linear across all INR ranges .

Also when you check INR of a normal person using coaguchek it’s spot on say 1.0 or 1.1 ….

That is my experience with comparison. Still I feel coaguchek very useful is to give you a broad trend of your INR weekly testing .
 

bece13

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Yes MdaPA, I review all the documentation and manuals and unless I have a condition that I'm not aware, there is no explanation. I only take Metoprolol, Warfarin and a baby Aspirin (81mg) no other drugs.
Pellicle - I tried different strips and same results
Brijeshb - interesting... for me, if is 2.3 or 2.8 it shows the same difference of 0.8-1.0.

I will use my device weekly but only compare it to the lab once a month unless I get a weird reading on my device. Looks like my INR is stabilizing.
 

pellicle

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What I have found while comparing INR lab tests and my coaguchek is when ever lab results are between 2.3 and 2.6 coaguchek will show around 2.8 . As and when the INR increases the gap between lab results and coaguchek also widens . Say for eg when the lab results show 2.8 or 3.0 coaguchek will show 3.7 or 3.9 . So I guess the accuracy is not linear across all INR ranges .
This is a reasonably well documented issue. From this 2007 article:

1628372494295.png


however its not really significant because of the idea of "clinical significance". Clinical significance means what will you do with the information?
  • keep the same dose
  • adjust the dose up
  • adjust the dose down
  • by how much?
If your INR target is 2.5 and you see INR=2.8 would you change dose? What about INR=3.1?

We may know from our well documented personal history that our INR fluctuates and we will know what it was last week. One should not alter doses on a single reading but use the idea of a trend forming. If there is a trend high then alter dose, if not then its probably this management rule
1628372794872.png


Naturally you'll test again next week to see if the trend has continued or the INR is back where it should be.
 

pellicle

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What if your INR was 1.9 or 1.8 (with range 2.0-3.0)? Would you adjust then?
yes, but its already established that the error brjshb asked about is less at lower levels ... I have no desire (or fantasy it brings any benefit) to be 1.8 even if I had an On-X.
I believe I've made my views pretty clear on how I adjust and why and for what reasoning:

 

dick0236

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[QUOTE="MdaPA, post: 909545, member: 17405}

What if your INR was 1.9 or 1.8 (with range 2.0-3.0)? Would you adjust then?
[/QUOTE]

If your range is 2-3 I would not change but I would watch my INR over the next few tests. If it stayed at the 1.8/1,9 for a couple of tests I'd add a little to my dose. However, since my range is 2.5-3.5 a 1.8 makes me nervous. I'd bump my dose up 10%-15% if I got <2. I am concerned about low INRs and strokes.
 

pellicle

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Dick
but I would watch my INR over the next few tests.
indeed more complete answer ... yes I'd do that too ... Missing from this question is any context, such as what was the previous reading.
Short answer for me is that even if it had been 2.4 before I'd give myself 50% more as a one off and look again next week. I always look again next week.
 

MdaPA

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my range is 2.5-3.5 a 1.8 makes me nervous. I'd bump my dose up 10%-15% if I got <2. I am concerned about low INRs and strokes.
Hi Dick,
Regardless of what you were the prior test/week, if you got a 2.3 or 2.4 just below your range of 2.5-3.5, would you bump up your dose or stay the course and wait until your next test to see what it is?
 

dick0236

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Hi Dick,
Regardless of what you were the prior test/week, if you got a 2.3 or 2.4 just below your range of 2.5-3.5, would you bump up your dose or stay the course and wait until your next test to see what it is?
No. A single test that was only .1 or .2 out of range would not trigger a dosing change unless it shows a trend of low INR over time. Those blips are usually just outliers and self-correct by the next test.
 

tom in MO

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No.


No.

What if your INR was 1.9 or 1.8 (with range 2.0-3.0)? Would you adjust then?
My range is 2-2.5. I run 2.4 +/- 0.2 about 85% of the time on my current dose for the last 18 months. If I come up with a 1.9, I don't adjust. I test in a week to 10 days to make sure it doesn't drop. I generally test every 2 weeks. If I come up 1.8, I drop 0.5mg off that day's 4 or 4.5 mg dose and test in a week to 10 days. On the high end, I adjust if >2.8, the same 0.5 mg or ~12%.
 

Cactus52

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Just for reference. This week I used my meter which is the coaguchek Xs and got a 2.4, dr. uses the same meter and got 2.6. Then I did a blood draw with Labcorp and got a 2.2. This was in a space of about 90 minutes. I try to keep it between 2.5-3 for a little safety margin.
 

Protimenow

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All three values are within the prescribed 20% range of accuracy for INR testing.
Personally, I would be a bit more comfortable when the lab's values are closer to 2.5 - this way, even if the 'real?' value is 20% lower, your INR is STILL above 2.0.
 

jlcsn2015

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I talked to Coagucheck/Roche AG support about it, they told me, there always be differences between methods, and times during the day, set your routine and stick to one method 80% of the time; if in doubt, call Roche/Support, they will send you a TEST Kit to let you know if your unit is working within parameters. I did that 4 years ago almost at the begining and it was all good. Ranges, i started with 1-5 - 2.0 with weekly testing, got tired of the frecuency and moved up to 2.0 -2.5 every 2 weeks test for 5 years; then recently due to other health concerns my target is now 2.0 and test weekly; Like others have explained many times, it takes 3 days for your INR to change, is not Tylenol.
 

Protimenow

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Because it takes about 3 days to see the effect of your dose of warfarin, I don't understand why time of day that you test is significant.

This is especially true if you take the same dose every day.

---

Jlcsn 1500 -- you didn't indicate WHY you were originally shooting for an INR of 1.5-2.0 -- do you have Afib? Do you have an On-X valve and believed your surgeon when she said that your range should be 1.5 - 2.0?

And what does frequency of testing have to do with shooting for an INR between 2.0 and 2.5? Would you test less often if your INR was lower?

Even with an On-X valve, you won't feel the difference between 2.0 and 2.5 (or 3.0) - and your risk of stroke would be lower than it is with the On-X recommended 1.5 - 2.0.

Test weekly. Consider shooting for a 2.5 target value.

Get lab draws occasionally (with my new doctors, it's every few months - I've gone monthly, and I've gone 6 months between lab tests, and just confirmed that my meter results are 'close' to the lab results. I've gone to more than one lab in a day, and gotten significantly different results from lab to lab. INR testing is more art than science.)
 
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ATHENS1964

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Oct 19, 2019
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On an issue that concerns many I had installed new batteries in April after
36 measurements inr today gave me a warning to replace the batteries.
until then Ι had not received any error message on screen which means that maybe I could make 1-2 extra measurements .
 
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