CoaguChek XS vs Coag-Sense - quick review

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Protimenow

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I have a CoaguChek XS and Coag-Sense meter, and a few years since I began using the Coag-Sense exclusively, I thought I may do another test of the CoaguChek XS to see how I feel about it now.
I bought two CoaguChek XS test strips, without checking the lot number, for $5 on eBay. I figured that this would at least get me a feel for the meter.

Surprisingly, when I powered it on, it still started after many years. The clock was 30 minutes off, but the meter powered on. I replaced the batteries, to improve the chance of doing a good test.

My first test was with the Coag-Sense PT2. I've used it many times before, incised my finger, used the transfer tube to draw blood into the tube, then deposit it onto the strip, and the test ran properly. My PT time was 39.8, and INR was 3.2.

I then inserted a CoaguChek XS strip into the CoaguChek XS. I'd forgotten, over the years, to press the M button on the meter to confirm the chip code. The user manual reminded me of this. After a period of warming up, the meter asked me to deposit blood onto the strip. I touched a newly incised finger, with a drop of blood, onto the side of the strip and got a 5 error - not enough blood. This was one of two strips that I had, shot to hell.

Apparently, transferring blood onto the CoaguChek XS strip wasn't quite as easy as I remembered it to be.

I decided to use a Coag-Sense transfer tube to collect and deposit the blood for my second test. I inserted the strip, confirmed the chip code, then waited until the meter asked for the blood, then incised my finger, collected blood with the transfer tube, and transferred the blood onto the CoaguChek XS strip. After a minute or so, the meter reported an INR of 6.5 and a prothrombin time of 77.6 seconds. This sure SEEMED like an error that last year's group of recalled XS strips would make. I checked on a recall list and found that the strips that were so cheap were part of the recalled lots.

I learned a few things:

Depositing blood onto the CoaguChek XS strip may not be easy for everyone. Some people do better using a capillary tube to draw the blood in from the finger, and to transfer it onto the strip. Taking this extra step is little different from the 'extra step' some Coag-Sense users have complained about on this forum.

The CoaguChek XS starts as soon as a strip is inserted, Coag-Sense takes a while longer before a test can be made.

CoaguChek XS meter batteries can last a LONG, LONG time.

I can't compare the readings of the two meters to each other because I had a bad batch of XS strips.

The Coag-Sense testing runs very smoothly, once you've done a test or two (which I had to do when I got my 'classic' meter years ago. It may take a bit of practice to use the transfer tube the first time or two that you test it - once you get the hang of it, testing is easy.

I'd like to, some day, get some new CoaguChek XS strips from a good lot and again run some comparison testing against the Coag-Sense. (If anybody here has some extras, with code strip, that they don't expect to use, I'd certainly like to try them).
 

pellicle

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Hi

I learned a few things:

Depositing blood onto the CoaguChek XS strip may not be easy for everyone.
I still recommend my method:

further if you look at one of your strips you'll see that the side of the strip (along the edge in the clear area) is a capillary transfer tube except direct into the strip, so if you also touch the side of the strip instead you'll get every last bit of blood sucked off and in.

fig2.jpg


These days, I need to put my glasses on these days and be steady of hand.
Also, its worth noting the advice from Roche (not saying you didn't, just saying)...

fig1.jpg


during warm up I stand (and have my arm hang by my side, if my finger isn't turning pink (like it looks white because circulation is bad or you're cold, then another method is "have a shower first" and then do it in the bathroom .. my house is often 7C inside (because "it doesn't get cold in Queensland)
https://cjeastwd.blogspot.com/2017/06/cold-inside-house.html


Too bad about those strips, but that result is considerably outside the Roche range for their declaration of the influence. Myself I'd want to (as always) have a comparison with:
  • machine X
  • machine Y
  • Lab Vein draw
Best Wishes
 
Last edited:

marvsehn

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Lynchburg, VA
I have a CoaguChek XS and Coag-Sense meter, and a few years since I began using the Coag-Sense exclusively, I thought I may do another test of the CoaguChek XS to see how I feel about it now.
I bought two CoaguChek XS test strips, without checking the lot number, for $5 on eBay. I figured that this would at least get me a feel for the meter.

Surprisingly, when I powered it on, it still started after many years. The clock was 30 minutes off, but the meter powered on. I replaced the batteries, to improve the chance of doing a good test.

My first test was with the Coag-Sense PT2. I've used it many times before, incised my finger, used the transfer tube to draw blood into the tube, then deposit it onto the strip, and the test ran properly. My PT time was 39.8, and INR was 3.2.

I then inserted a CoaguChek XS strip into the CoaguChek XS. I'd forgotten, over the years, to press the M button on the meter to confirm the chip code. The user manual reminded me of this. After a period of warming up, the meter asked me to deposit blood onto the strip. I touched a newly incised finger, with a drop of blood, onto the side of the strip and got a 5 error - not enough blood. This was one of two strips that I had, shot to hell.

Apparently, transferring blood onto the CoaguChek XS strip wasn't quite as easy as I remembered it to be.

I decided to use a Coag-Sense transfer tube to collect and deposit the blood for my second test. I inserted the strip, confirmed the chip code, then waited until the meter asked for the blood, then incised my finger, collected blood with the transfer tube, and transferred the blood onto the CoaguChek XS strip. After a minute or so, the meter reported an INR of 6.5 and a prothrombin time of 77.6 seconds. This sure SEEMED like an error that last year's group of recalled XS strips would make. I checked on a recall list and found that the strips that were so cheap were part of the recalled lots.

I learned a few things:

Depositing blood onto the CoaguChek XS strip may not be easy for everyone. Some people do better using a capillary tube to draw the blood in from the finger, and to transfer it onto the strip. Taking this extra step is little different from the 'extra step' some Coag-Sense users have complained about on this forum.

The CoaguChek XS starts as soon as a strip is inserted, Coag-Sense takes a while longer before a test can be made.

CoaguChek XS meter batteries can last a LONG, LONG time.

I can't compare the readings of the two meters to each other because I had a bad batch of XS strips.

The Coag-Sense testing runs very smoothly, once you've done a test or two (which I had to do when I got my 'classic' meter years ago. It may take a bit of practice to use the transfer tube the first time or two that you test it - once you get the hang of it, testing is easy.

I'd like to, some day, get some new CoaguChek XS strips from a good lot and again run some comparison testing against the Coag-Sense. (If anybody here has some extras, with code strip, that they don't expect to use, I'd certainly like to try them).
Just a note. I have some of the old strips from the recall. But I never did see any difference in my results!
 

LondonAndy

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I would certainly agree that there is a learning curve to getting the right size drop of blood in the right place on the XS, but I imagine it took a bit to learn the Coag-Sense transfer tube method too, so perhaps more than 2 test strips might be needed to get through that stage. It is an interesting exercise, with not many in the position to undertake it, so thank you for trying and sharing.
 

Protimenow

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Aug 10, 2010
Messages
2,277
Location
California
Hi



I still recommend my method:

further if you look at one of your strips you'll see that the side of the strip (along the edge in the clear area) is a capillary transfer tube except direct into the strip, so if you also touch the side of the strip instead you'll get every last bit of blood sucked off and in.

View attachment 887127

These days, I need to put my glasses on these days and be steady of hand.
Also, its worth noting the advice from Roche (not saying you didn't, just saying)...

View attachment 887126

during warm up I stand (and have my arm hang by my side, if my finger isn't turning pink (like it looks white because circulation is bad or you're cold, then another method is "have a shower first" and then do it in the bathroom .. my house is often 7C inside (because "it doesn't get cold in Queensland)
https://cjeastwd.blogspot.com/2017/06/cold-inside-house.html


Too bad about those strips, but that result is considerably outside the Roche range for their declaration of the influence. Myself I'd want to (as always) have a comparison with:
  • machine X
  • machine Y
  • Lab Vein draw
Best Wishes
Thanks, Pellicle.

Your method is excellent if you're having a problem getting an adequate drop of blood for testing. I've used it in the past when working with CoaguChek and InRatio. FWIW, I usually do pretty well getting a good drop after shaving - my fingers are warm, and the motions necessary for shaving seem to help with blood flow.

In the case of the review, I can get a good drop of blood - and haven't had to use all the steps you listed (although I used them, with some dental floss, years ago, when using other meters). Now, I usually am able to squeeze enough blood into the tip of the finger before lancing it so that I can get a large enough drop. The problem I had with my first strip was placing it on the side of the strip - the strip didn't seem to draw it in quickly enough. I'm not sure what happened.

As far as testing with other meters - this is what I was doing. I tested first with my Coag-Sense meter. My interest in the CoaguChek XS meter was a) to compare the results and b) to see about ease of use comparisons.

The XS, in retrospect, back when I was using it frequently, made it easy to deposit blood into the strip. I'm not sure what went wrong with the first strip, but I didn't want to risk wasting the last strip, so I used a transfer tube to make sure I had adequate blood (and no air) when I used the second (and last) strip.

The second test with the XS was way off, demonstrating the error in this defective lot. (It's possible, too, that these strips were also mishandled before I bought them, resulting in an error that was WAY OFF). The two strips came from a vendor who lost a near relative - they were the last two in a tube of six. I don't know how they were handled before I bought them.

Of course, I have no faith in that result, but I was able to run a test on the meter to evaluate ease of use.

I'm not sure whether I'll try to get a few strips or just sell the meter and raise some much needed cash.
 
Last edited:

Protimenow

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Marvsehn -- you said that you saw no difference. Was this no difference between tests using your meter and one at a clinic, or between lots of strips on your meter?
It's certainly possible that many strips from your recalled lot were fine to use, and Roche recalled them out of an abundance of caution.

I'm glad that these strips worked well for you.
 

Protimenow

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LondonAndy - yes, until I re-read the instructions for usint the new transfer tubes, I DID waste a couple strips. This was purely user error.
Now, it takes nothing extraordinary to use the tube - prepare and incise the finger, squeeze a drop if one doesn't already form, touch the tip of the tube to the drop of blood, watch the tube take it in until it touches a small white 'stopper', put the tip of the tube into the well in the strip, then push the little plunger on the tube. This sounds a lot more complicated than it really is.

At first, I didn't touch the tip of the tube into the well on the strip and introduced air into the sample. It's very easy to collect and apply the sample now.

One point worth mentioning: with Coag-Sense, as long as you don't drop any blood in the well, the strip can be used after the clock times out. You're not wasting a strip by not applying the drop quickly enough. The CoaguChek XS gives you 180 seconds - after that, the chip can't be reused. WIth the Coag-Sense, if you can't deposit blood quickly enough, the strip can still be used.

I wasted a few Coag-Sense strips until I figured out that the tip of the tube should contact a point in the well. I don't expect to waste any more strips using the Coag-Sense transfer device.
 

Keithl

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Messages
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I actually am liking the CoagSense, I go the hang of the transfer tube right away. I have not wasted a strip yet. I did bring it to the clinic today to compare to their CoagCheck XS. 2 different finger about a minute part they got 3.1 I got 2.8. Considering what as been said about the CoagSense reading a tad low and the CoagCheck XS reading high I think I can confirm that, so I assume I am 2.9-3.0.

My home service starts this weekend and I plan on do a few cross compares then using my meter. Only reason I am getting the service is because I hit my max out of pocket so it will be free and it is the only way the doctor will take my numbers now. I hope to show her in 6 months that I have this well controlled and ask her if I can stop the service and just email numbers once a week or let them now when out of range and supply numbers since last test.

I am tracking everything in a spreadsheet.
 

Protimenow

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Keithl - I'm glad you're recording your readings and other info. I've read from others that presenting a spreadsheet to the doctor can show that you're keeping on top of things.

When I was testing with the Coag-Sense and the CoaguChek XS, I often found that blood draws gave an average of the two meters.

I've been managing my dosing for years - I've also had an anticoagulation clinic doing testing and making recommendations. The recommendations weren't always what I'd agree with. (There are dosing calculators and dosing advice elsewhere on this site).

Because I was able to manage my INR and was always in range when I went to the clinic, they moved my visits from weekly to twice a month to monthly and eventually bi-monthly. They called me Mr. Consistent. The idea of testing every month or two scares me. This is another reason to have my own meter and do my own testing -- I can tell week to week what my INR is.

As far as your doctor is concerned, will she refuse to see you if you stop using her service?
 

Keithl

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I do not think she would refuse to see me, but I suspect they will not write warfarin prescriptions if they do not agree with what I am doing. She seems very good, and since I am a new patient I figure I do the service since it is free, keep anal records, and when I see her in six months make the proposal and see what she says. The clinic nurse is already following my lead for my dose recommendation. On,y issue was a temp nurse was there yesterday and she was afraid to change anything. I told her in 4 weeks my range changes from 2-3 to 2.0-2.5 so if I am 3.1 and been 2.9 for 2 weeks we should start lowering my dose to get me closer to 2.5. She just said to stick with what I am doing. Of course I made the mistake of saying I missed my vegetable juice 2 days again and she assumed that is why I was up .2. I will tell you these clinic people scare me, I am doing a far better job managing my INR than they are.

They also won’t write more than 30 script for meds at a time, another annoying thing. It looks like 5mg and 1mg will be my go to sizes to hit my range so why not give me 90 days?
 

marvsehn

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Marvsehn -- you said that you saw no difference. Was this no difference between tests using your meter and one at a clinic, or between lots of strips on your meter?
It's certainly possible that many strips from your recalled lot were fine to use, and Roche recalled them out of an abundance of caution.

I'm glad that these strips worked well for you.
Between lots for my meter.
 

Protimenow

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Keithl: You shouldn't have to worry if your INR is between 3.0 and 3.5. Personally, I only get slightly concerned when my INR gets close to 4 - and even then, it's not that big a deal. Besides, it's hard to hit a small target like .5.

I didn't review which valve you have, but even with an On-X, you're not doing any damage by keeping your INR above 2.

I can sort of understand why your doctor isn't prescribing more than 30 days at a time initially. If you had your OHS recently, it can take time to regulate your INR.

For myself, I just dropped my dose from 7.5 to 7.0. 7.0 is a bit tricker than one 7.5 mg (or three 2.5 mg) doses -- I take a 4.0, 1/2 of a 4.0, and a 1.0 to get it to 7.

I know it must have been a typo, but do you mean you 'keep anal records' -- wouldn't a spreadsheet be easier to use?

ALso - since you get the service at no cost, it's always good to have a second meter to compare your results, and an occasional blood test to confirm the accuracy of the lab or the meter. (I just had my second experience in 7 months with a lab screwing up a value. I'll write about this soon in a new thread).
 

Keithl

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I actually have an On-X and the surgeon said after 90 days he set a range of 1.5-2.0, but I talked to my new cardiologist and said I adorn want to go that long and would prefer 2.0-2.5 with a target of 2.5.

I understand the 30 days only limit for now. I was not phased with 3.1 and likely would not be concerned unless I was above 3.5.

I have 2 supplements I was taking (garlic and fish oil) both which potentially can impact INR so my guess is they may bring me down a tad. I have been fairly stable now for 3 weeks.
 

tom in MO

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I actually have an On-X and the surgeon said after 90 days he set a range of 1.5-2.0, but I talked to my new cardiologist and said I adorn want to go that long and would prefer 2.0-2.5 with a target of 2.5.

I understand the 30 days only limit for now. I was not phased with 3.1 and likely would not be concerned unless I was above 3.5.

I have 2 supplements I was taking (garlic and fish oil) both which potentially can impact INR so my guess is they may bring me down a tad. I have been fairly stable now for 3 weeks.
It's not possible to hit a target of 2.5 with a range of 2-2.5.

Target is meaningless in INR, it's always a range. There is no correct number, just a correct range.

You may have a median value or you may have an average value, but there is no need to adjust your warfarin dose until you are out of range.

I keep my INR 2-2.5 as prescribed and am usually within range. Some have said it's too hard to keep to a 0.5 range, but I've done it for 7 years without difficulty; testing every 2-3 weeks and more frequently if out of range.
 

Protimenow

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Personally, I'm more comfortable if my meter puts me mid-range or slightly higher. There's more risk of stroke or TIA if the INR drops below 2 (even if I had an On-X, I'd rather not take risks by shooting for 1.5). Being above 2 doesn't change your life.

One thing that I note, too, is whether or not my meter reports values above or below those of lab values. For example, if a 2.0 on my meter was a 1.7 or 1.8 in the lab, I'd be a bit concerned, and probably shoot for a 2.5 on the meter just to give myself a bit of a cushion. OTOH, if the meter reported at, or slightly below the lab INR, a 2.0 might be 2.0 - 2.4 (or so) in a lab, and I'd feel pretty comfortable with that knowledge.

Learning your meter, and the relation of its values to a trusted lab (and they can't all be trusted to always be accurate) is an approach that can help to keep your INR in range - and alert you when it isn't.
 

Keithl

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Quick update. It seems that very consistently the gap between the the CoagChek XS and the CoagSense PT2 seems to be .3 with occasional .2 with the CoagSense being lower than the CoagCheck. Friday I am getting blood work and asking for a lab INR and will compare those results to the meter.
 

pellicle

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They also won’t write more than 30 script for meds at a time, another annoying thing. It looks like 5mg and 1mg will be my go to sizes to hit my range so why not give me 90 days?
my GP was initially a bit cautious about me going out on my own, but when I presented my Spread Sheet of data on the end of the first 3 months he was pretty impressed.
When I next met my cardio (a year later) he asked how I was going and I showed him my SS and he was super impressed, spent a few minutes going through it and liked my layout. He mentioned that one of the biggest problems was "compliance" (actually taking the stuff) and was super impressed that my INR was "quite stable" (which gives me a laugh when I see people here "freaking out" when they think their INR has made a huge change but its within my range). His view is that anywhere between 2 and 4 is good to go (as indeed studies show).

This graph is one of my more difficult management years, it goes to show how weekly testing can assist you for staying on top of things.

887146
 

Keithl

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I have a similar spreadsheet I have started along with comments for anything worthy of mentioning that might impact a reading. My hope is to do same with my cardiologist after a few months so they will just write me 90 days of 5mg and likely 1mg at this point. I just had to spilt a 2.5 into 4 to bring my INR just inside the range.
 

Protimenow

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I keep a supply of 7.5 mg, 4 mg, and 1 mg. I rarely make changes to my dosing, but with that combination, I'm able to get most of the values that I want. (Perhaps I should get 5 mg instead of 7.5 - for a bit more flexibility)
 
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