Coaguchek XS accuracy

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Shiv

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Hello all,
I had a mitral valve replacement in 2019, I was 29 years old. On- X valve. I recently bought a coaguchek xs machine. Should I trust the readings of this? Or should I compare with my labs? Are the labs readings accurate? My 2 readings with my coagucheck was 2.1 on 29th jan and 2.6 on 31st Jan. ANYONE any experience on coaguchek xs machine?
 

pellicle

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Hi
I had a mitral valve replacement in 2019, I was 29 years old. On- X valve. I recently bought a coaguchek xs machine. Should I trust the readings of this?
that's an excellent (if not amazingly common) question. Firstly I'd say "yes" but with a qualifier. The qualifier is the operator. When I started with my coaguchek I found my readings were off a little, but I refined my technique and followed strictly the guidelines by Roche and within a very short time was no more than 0.2 INR points away from labs.

A quick summary from here: Accuracy and clinical utility of the CoaguChek XS portable international normalised ratio monitor in a pilot study of warfarin home‐monitoring

Conclusions
In the hands of patients the CoaguChek XS showed good correlation with laboratory determination of INR and compared well with expanded and narrow clinical agreement criteria. Both patients and doctors were highly satisfied with the accuracy and ease of use of the CoaguChek XS.​

The labs (who stand to lose an easy money stream) are of course the primary poo-hooers of this technology, but not in Europe where everyone is behind it for the simple fact that it delivers better outcomes to the patient and lowers health care costs.

Roche points out a few things:


which brings us to an important point: INR is not like measuring a piece of steel and is a lot more "rubbery" around the edges. It is for this reason you should NOT think in terms of a range but in terms of a target. Thus if you're trending away from the target (but still in a safe range) then you should use that to inform what you do next (assuming you're managing yourself).

Now its important to determine that you do not have one of the very rare blood issues that cause errors in determining INR with these machines, but as that's 1% or less of the population that's probably not you

Once you know you're not in that group then the accuracy has been reported very well in a number of separate studies: Eg


and


I'd say that the Roche Coaguchek is used by the vast majority of users here.

Lastly if you're going to be managing your own INR (or if you just want to understand it more) I've got a blog post on that which some have found helpful (although its lengthy and detailed)

 

Shiv

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Jan 31, 2021
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Location
Mumbai, India
Hello all,
I had a mitral valve replacement in 2019, I was 29 years old. On- X valve. I recently bought a coaguchek xs machine. Should I trust the readings of this? Or should I compare with my labs? Are the labs readings accurate? My 2 readings with my coagucheck was 2.1 on 29th jan and 2.6 on 31st Jan. ANYONE any experience on coaguchek xs machine?
The next 2 readings on coaguchek were 3.3 and 3.4 and lab test was 3.0. Coaguchek looks good in initial testing. Will compare more and post the results. Also I will save the data and post on graph and will check the TTR- time in therapeutic range ...I aim to reach 95% TTR
 

elMIguel

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I'm taking the plunge. I just purchased a used Coaguchek XS off eBay. Until it gets here I'll be reading through all the great advice and guidance to help me get off on the right foot. I have an appointment to get my INR checked from the clinic on the 22nd and plan to check it myself the morning before to see how closely they are in sync.
 

pekster11

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I'm taking the plunge. I just purchased a used Coaguchek XS off eBay. Until it gets here I'll be reading through all the great advice and guidance to help me get off on the right foot. I have an appointment to get my INR checked from the clinic on the 22nd and plan to check it myself the morning before to see how closely they are in sync.
my coaguchek meter has been a big help since my surgery in april
the ability to keep a close eye on your INR when you begin to take warfarin is invaluable
 

elMIguel

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my coaguchek meter has been a big help since my surgery in april
the ability to keep a close eye on your INR when you begin to take warfarin is invaluable
My surgery was in March. Everything about it was overwhelming so I didn’t have a problem with the clinic taking my INR for a while. I feel that I’m ready for this now.
 

Cactus52

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I purchased one on eBay late last year and I have been very happy with it. When I go to my cardio he uses the exact same model. I brought mine a couple of times and I get readings now usually the exact same or .1 off. When I do my lipid panel next month I'll check it there as well.
 

Lynn

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Though I have had a coaguchek from the onset, I also lab tested for the first couple of months, mostly to keep my medical team happy. I tested using two different lab systems, one through our hospital network, and another at a private lab company that contracts to our public health care system. Interestingly, the private lab was always bang on with my coaguchek. The hospital lab always differed slightly. Usually one to two points lower than my meter. (ex: meter 2.3, lab 2.1). My point being, that while there can be slight differences in readings, I feel my meter is very accurate and I now feel comfortable with just home testing. It is so easy and so convenient. Plus for some reason going to the lab all the time made me feel like a sick person, where as home testing doesn’t.
 

Chuck C

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I feel my meter is very accurate
I also believe my Coaguchek to be very accurate, the few times I have been able to compare results with the lab.
Plus for some reason going to the lab all the time made me feel like a sick person, where as home testing doesn’t.
I know what you mean. One benefit of home testing. For those times when I have to get labs done, I am very glad that they now have an option to wait in your car and have them text you when it's your turn (I actually choose to go for a walk as I wait for the text). When sitting in the lobby it is always a funny feeling. Can't help but wonder what diseases might be carried by the other folks waiting to get labs- trying to determine what is making them sick? Is it contagious? Thanks, but I'll go for a walk and wait for the text, lol.
 

pekster11

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yes, i trust my coaguchek meter alot.
i have been comparing it's results to blood draw results
always v close
coagucheck is usually a touch higher though
for example on monday i used my coaguchek and got 2.4, a few hours later i had a blood draw at the lab and got 2.2
 

BillDaThrill

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When I returned back home to my small town after surgery with my shiny new mechanical valve, I made my first visit to my cardiologist's office 'coumadin clinic'. I was surprised to see them use the coaguchek meter. I thought they would have something more sophisticated or take a blood draw. Have visited the clinic three or four times since and am closing in on keeping my INR (~2.3) and warafin dose (32.5 mg/week) steady. Do you think I am good with the coaguchek only or should I visit a lab for a blood draw a few times a year? So far, they seem to do a great job with taking the sample and my double insurance is making it free for me so I figure no reason to buy my own unit yet.
 

tom in MO

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When I returned back home to my small town after surgery with my shiny new mechanical valve, I made my first visit to my cardiologist's office 'coumadin clinic'. I was surprised to see them use the coaguchek meter. I thought they would have something more sophisticated or take a blood draw. Have visited the clinic three or four times since and am closing in on keeping my INR (~2.3) and warafin dose (32.5 mg/week) steady. Do you think I am good with the coaguchek only or should I visit a lab for a blood draw a few times a year? So far, they seem to do a great job with taking the sample and my double insurance is making it free for me so I figure no reason to buy my own unit yet.
I've been doing home testing for ~7 years. I've had two cardios during that time, none of which deemed it necessary to check my meter with a blood draw. Same with my internist. If there was a need, the litigious nature of our society would result in the manufacturer requiring it, especially since the expense would be born by the patient's insurance.
 

LondonAndy

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I've also been using my CoaguChek XS for about 7 years, and trust it completely. Every 6 months I go to my anticoagulation clinic and check my result against theirs. Initially they did a lab test for their check, but these days they use the 'multi-patient' version of the CoaguChek. I have never been more than 0.2 different from theirs.

This week I have been on antibiotics, which always push my INR high. Having the ability to home test meant I could increase my frequency of testing (to every 3 or 4 days) and make a sensible adjustment to my Warfarin dose to compensate when I went over range. Great to take on holiday too, not worrying about a different diet and more alcohol than usual.
 

Chuck C

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I've been using Coaguchek xs for about 5 months.

I have found my lab values very close to my home testing results, but had only checked it several hours from the lab blood draw and decided to time my next comparison as close as possible to the lab blood draw.

On yesterday's INR blood draw, I had the Coaguchek waiting in my car, which would allow for a quick comparison. I was able to complete my self test within about 5 minutes of the lab blood draw. Both values came back with an INR of 2.2.
 

tom in MO

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Hello all,
I had a mitral valve replacement in 2019, I was 29 years old. On- X valve. I recently bought a coaguchek xs machine. Should I trust the readings of this? Or should I compare with my labs? Are the labs readings accurate? My 2 readings with my coagucheck was 2.1 on 29th jan and 2.6 on 31st Jan. ANYONE any experience on coaguchek xs machine?
The lab results are the "gold standard" that the coaguchek was verified against.
 

Protimenow

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Chuck C - INR is a very slow moving number. Whether you take your INR minutes after a test or hours after a test, the INR would probably be the same. Unless you're taking a high dose of Vitamin K1, your INR will be stable for many hours.
Even with high doses of K1, it takes HOURS to see INR drop.

So - the next time you want to compare your meter's INR to your lab's, get your blood drawn, have lunch, relax a little, THEN use your meter to check your INR.

(Or, vice versa, have a good breakfast, relax a bit or do some work, THEN get the blood draw. A few hours between tests will make no difference).

FWIW - I had a really strange INR from a lab that my Doctor's office used. In order to get to the truth, I tested with my meter, then went to two other labs for testing. My meter and the other two labs had results similar to my meters, and about 1.5 INR lower than the erroneous lab.
I reported this to my doctor, who thanked me, because he had another patient with the same, erroneous INR, and was about to change her dose because of the incorrect test results.
 

Chuck C

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NR is a very slow moving number
So - the next time you want to compare your meter's INR to your lab's, get your blood drawn, have lunch, relax a little, THEN use your meter to check your INR.
Yes, I am very much aware that INR moves slow due to the long half life of warfarin. However, everything else being equal, I prefer to take the reading as close as possible to the blood draw

- It is just as easy to check it right after my blood draw as waiting hours. It also reduces the chance of variance with the passing of time in my INR, even if that variance would likely be minimal.
-If I wait hours and go about my day, I just may forget to take my INR later on, so I'd rather get the spot check while it's fresh on my mind, as I am forgetting things more as I get older :)

Having said that, I don't plan to be checking my INR at the lab again any time soon, unless I start getting strange readings from my meter. The checking I have done would suggest that mine is not a lemon and I expect to get many years of accuracy from it.

I got a strange message from the Coumadin Clinic today, after my results came in. Since my cardiologist ordered the INR, and not the clinic, I expected that only he would get my results from the lab. Apparently, they still have it set up so that the clinic gets my INR resutls, even if ordered by another physician. The problem is that I have not communicated with the clinic in months and they are unaware that my cardiologist has changed my target range from 2.5-3.5 to 2.0-3.0. So, they see 2.2 and send me a message and leave a voicemail that I am out of range and then took the initiative of prescribing an injectible anti-coagulant which I am supposed to use to bridge me until my INR gets back in range. Except, I am not out of range, lol.

They then give me guidance for warfarin dosage to get back in "range". The problem is that their data is old, from back when I was only taking 4mg/day. I now take 6.5mg/day.
So their guidance went:
Thursday 6mg
Friday 4mg
saturday 4mg
Sunday 4mg

Since they have not communicated with me in over 4 months, shouldn't they check to see my current dosage before they give me guidance?

If I followed their guidance, it would really put me under range, as I need 6.5mg per day to keep INR between 2.2 and 2.6.

And for this "guidance, which was not wanted, they were going to invoice me $ 500. Just kind of nuts. I called and explained and so hopefully they will retract the billing.
 

Protimenow

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Chuck:

I used to do the same thing, testing with meters close to the time that I test at the lab. It just seems a bit easier and, as you said, helped me to remember to test.

I was forced to use my HMO's 'coumadin clinic,' even though I've been self-managing for 12 years. The director is an idiot know-it-all pharmacist with a personality that I don't want to attempt to describe.

He canceled a standing order for lab testing, assuming, of course, that I no longer need any lab tests. I now have a standing order for testing by my PCP, who isn't a direct employee of the HMO.

I don't know if he'll hassle me about refills - I usually get 1, 4, 5, 7.5 mg, from which I can make practically any dose. I don't know if the four different dosages, at a single time, will bother him or not.

I wouldn't be surprised if the HMO's 'clinic' will also get a copy of the lab reports.

--

The issue with your 'clinic' getting results should, of course, be resolved as soon as possible. Their 'advice' is just another way of pulling money out of your wallet. If they DO try to bill you, you might point out that they did not bother to ask about your current dosage as prescribed by your current doctor and, as a result, would have prescribed a dosage that was not in line with your current needs and that could have been dangerous for you. Also - the fact that the lab erroneously sent them the results shouldn't be something that you should be on the hook to pay for. (And, FWIW, a tech who probably uses an outdated 'protocol' for adjusting dosage probably took about a minute to pull up your record, read a single number on the lab report, check what his little protocol says, and take a few minutes to call you. They want $500 for this $20/hr person who spent ten minutes? This works out to $3000/hr for their 'services.'

I hope that they do NOT get away with trying to bill you for an unwanted, and unrequested, service.
 

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