Self-testing machine for checking INR - AF Association

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Self-testing machine for checking INR


I am on warfarin having decided, for various reasons, not to go onto one of the new anticoagulant drugs. The only drawback is the regular blood testing. Has anyone any experience of the self-testing kits such as CoaguchekXS system?

I was slightly concerned to read the NICE guideline which state that if you are out of the therapeutic range (in my case 1.7) you should be tested more frequently than my warfarin clinic states i.e. fortnightly. So, thought I should get my own kit. Any views, recommendations would be greatly welcomed.

12 Replies

Hi Hilaire,

I am fortunate and have no problem with Warfarin and therefore do not need the new anticoagulants. I have had the Coaguchek XS device now for 6 years and at this stage am on 42 day tests - I have been as long as 70 day tests. I paid for my own device when I got it in 2010 and I get the test strips from the UK NHS on prescription. My experience over the 6 years is that you will get out of range from time to time and the chances are you will never know what causes that to occur. An isolated reading of 1.7 should just make you alert but not throw you into a panic.

My experience has been that as I have my own device and test strips at home I basically please myself as to the frequency I test. If I got a reading of 1.7 I would test 1 week later and if the reading were still 1.7 - or less then I would notify my GP or my clinic. My experience is that it goes up just as easily as it came down on its own. However, if you got consistently low readings then its a problem analysing why - so your GP or clinic may increase your dose according to a set of computer based algorithms which are used.

Now, when I am on 42 or 70 day tests I automatically test myself at 2 weekly intervals - the point is that on 42 or 70 ( or even longer as with some people) days, your readings would be pretty stable so there isn't too much of an issue. You don't say how long you've been on Warfarin or what your track record is with your readings so its a bit hard to comment further.

You might also be interested to know that I have had to come off Warfarin twice, 1) when I had a CT scan and no bridging anticoagulant was supplied and 2) last Nov when I had a partial knee replacement when I was given two short sharp doses of a bridging anticoagulant (Fragmin) and after surgery straight back on Warfarin again. No problems. None at all. In both cases from when I ceased Warfarin to when I returned to being in INR range it was 29 days. As I said - no problems.

I am still working, I go away from time to time and I also travel to Australia and I just pack my device, my test strips and my medications and away I go.

I make few concessions to Warfarin either by way of alcohol or food, I do eat green veggies but vary my intake - BUT diet wise what I eat and drink I do so with CONSISTENTCY. NO BINGING ONE WAY OR ANOTHER.

The thing with this device is that it returns to you control of your life - pure and simple ! It just gives more peace of mind.

So, as I said, if you got a low reading then use another test strip take a more frequent reading, and if you got another low or lower reading then have a chat to your medical practioner.

I am fortunate that my GP's practice supports the use of this device. I take a reading at the prescribed date, phone it through to the surgery, they phone me back about 4 hours later having fed my reading through their software (sometimes quicker), they give me my new dose ( and it may not vary from what I was already on) and my new test date. Bingo that's all there is to it. If its 70 days till the next test, I make sure I still test every 14 days but I only tell them the reading on the set - FORMAL- date, if you see what I mean. I don't tell them the in between readings, unless they go low, like 1.7 or lower, and remain there.

So, you will need to ensure that your GP or clinic support the use of Coaguchek XS and will help you with training and will support you for the initial period while you get used to it.

You will find the device has its own in built quality control which ensures that the test strip isn't defective so that when you drop your blood on the test strip you know the reading is correct. The device will actually flash QC and give a tick, so you know all is OK. If the test strip is defective or there is another problem it will send you an 'ERROR' message which will send you scurrying for your user guide which will identify the problem. In addition my arrangement with my GP includes the facility every 10 tests to go on and do a test on my device and the surgery's device. One finger prick, one drop of blood put on the test strips of 2 devices. That way it ensures your device is performing to surgery standards. It doesn't need to go back to Roche for checks unless you drop it or in some way mistreat it.

Hope that helps, if you have any questions just ask away.


Hilarie in reply to carneuny

Thanks very much John. I phoned up my GP's practice - they had no experience of self-testing perhaps because there is a warfarin clinic at King's where the blood samples are analysed so I will phone up that clinic on Monday. Your experience is certainly very helpful and I would feel a lot better being in control of the whole process.

I've used a Coaguchek for the last 6 years and found it brilliant. Really the best think I've bought. I test once a week and it enables me to stay in a tight range of 2.2 to 2.8 nearly all the time. I self manage as well - i.e. adjust my warfarin, and you may consider doing that in the future. I know my own body much better than the medics and 0.5mg up or down enables me to keep well in range. I very my diet a lot though I do try to take some Vit K each day, brocolli, kale, lettuce, etc. I also take a Vit K2 tablet.


Hilarie in reply to MarkS

Thanks Mark for the info. Very helpful.

I have had a coaguchek device for many years, I travel a lot and it has been a constant companion throughout enabling me to adjust should I need to. To aim for a rigid INR is, in my humble opinion, unrealistic, providing I stay within the therapeutic range of 2.5 to 3.5 I am perfectly content. I have full support from my GP, the surgery supplies the test strips and in return I give him my INR readings on a regular basis. Thoroughly recommend the device with one small caveat and that is to run your coaguchek against a path lab reading every once in a while - common sense really!

Thanks Annaelizabeth for your helpful reply. Judging from the comments I have had on the forum I think I should invest in a coaguchek device.

Loads of people here are self-testing, and many are self dosing. See some of my previous posts for comments on dosing. Most get on well with it. A few have arguments with GP etc to get free strips. A few face problems getting the freedom to self-dose. The only problem I faced with it was a practical one -- getting the blood drop in the right place. Too much blood was as bad as too little blood. I am good with my hands, so this problem was unexpected. Eventually, my wife watched and said, I could not see properly what was happening. Th exact centre was hidden by my finger! So, now I jab the finger. I go for one deep prick in a flieshy spot, then I relax, and my wife puts it on the centre of the strip. Rarely fails. Voila, the result a minute later. I adjust the dose, so no arguments.

Ask again if you want more information, medical references that show the benefits of self testing, etc

MarkS in reply to ILowe

I used to go for the centre but following comments on here I now touch the side of the strip with the bottom of the drop of blood and it gets sucked up. It's much easier to do and more reliable.

ILowe in reply to MarkS

Everyone has to find their own way. When I tried the side, the blood moved swifly to the other side, and then down the narrow funnel, then stopped just before the end. There was plenty of blood! I sometimes needed 5 attempts! Now by using the centre, I get it in one.

I also do one deep prick, in a place away from muscle. I now know the spot, and it heals swiftly, no hurt fingers, nothing to see. Depends a bit on your fingers.

PeterWh in reply to ILowe

The absolute key is to either find a LEVEL surface or one that slopes fractionally towards the Coaguchek machine with the strip in. I failed the first few times and then regularly and then I thought of the level. Put my spirit level on what appeared to be a level surface and Lo and behold it sloped away from the machine!!!

Like Mark I found the edge the best but the further edge viewing the strip from the side so you can easily see the strip and the blood drop. Each to his or her own.


I have a Coaguchek machine and find it invaluable . I normally test weekly and feel reassured by it. I am sufficiently experienced ....I make 0.5 mg adjustments in my warfarin dose as and when .

I particularly like to keep on range as I tend to get episodes of fast AF which are refractory to meds and usually need emergency DCCV.


Thank you so much for all your responses.

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