Rethinking Coag-Sense

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Protimenow

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I've used the Coag-Sense meter for about nine years. For the past year or so, I pretty much gave up on it, in favor of the CoaguChek XS for a few reasons:

Strips for the XS were easy to find.
Testing was slightly easier on the XS than on the Coag-Sense
Results were pretty consistent.
IF I had a doctor who also used the XS, my results would probably be almost the same as the doctor or clinic results.
It was easy to find good 'backup' meters - although I doubt that I'll EVER need one.

I moved away from the Coag-Sense for a few reasons:

Testing was marginally more of a process than with the XS
Supplies are not as easy to find (at least, not on eBay)
Results were consistently between .5 and 1.0 LOWER than XS results.
Coag-Sense results were frequently not as close to labs as the XS results.
I'm unhappy with the current management, their inability (or unwillingness) to respond to messages on their site, and the support that I've gotten from them. In fairness, the only time I interacted with Roche, support has been very good.

I just got some new strips - and a backup Coag-Sense PT2 (because of the price, and it also came with strips).

The results of both Coag-Sense meters were almost the same: 2.0 on Tuesday, and 1.9 on Wednesday. By contrast, on Tuesday, the XS gave me a 2.8.

My argument in support of the Coag-Sense that I made MONTHS ago, and seemingly forgot is this:

I'd rather have a meter that gave me a test result that was LOWER than my actual INR than one that gave me a HIGHER than actual result.

In other words, if the Coag-Sense gave me a 1.9, and the XS gave me a 2.8, I would feel far safer to slightly increase my warfarin dose - EVEN IF THE ACTUAL INR WAS SOMEWHAT HIGHER - just to be sure that my INR doesn't get BELOW 2.0.

I'll try to get some Coag-Sense strips, and for a while may use both meters. I feel a blood test coming soon -- to compare results to both meters and try to make a decision about which appears to be most accurate.
In other words, if I want to
 

pellicle

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Its been a journey ...

1658392021071.png
 

Protimenow

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Yes.

It certainly has.

And it seems to be a solo journey.

From my test of three or more competing meters (and labs) years ago to comparing the two meters to each other and lab results, I've pretty much been on my own here. Now, if I can only convince a doctor to leave a standing order at a lab, my trifecta may be complete.

(FWIW - if I find that the XS is always pretty accurate, and that it accurately reports INR values between 2 and 2.5 (so I know that it's not missing the low INRs), the Coag-Sense would be of little value to me. The Coag-Sense is only of use when it identifies low values (below 2 and up to aroujnd 2.5) that the XS misses.
 

Chuck C

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In fairness, the only time I interacted with Roche, support has been very good.

The one time that I interacted with Roche customer support I was very impressed. They answered the phone quickly; totally professional; and took care of my issue right away.
 

Protimenow

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I might try to get up the chutzpah to call Roche and see if I can get a strip guide and perhaps a battery cover for one of my $29.95 XS monitors. There are alternatives to the strip guide - but it might be nice to have my old backup equipped to work without the hacks.

Roche support has been very good. Coagusense (the manufacturer/distributer) has sucked so far.
 

ETC908

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Thought I'd mention that I too have had the same experience with the Coagsense vs. the Coagucheck. I bought the Coagsense before my surgery this past November as I wanted a system already in place when I got home (in the US, the Coagucheck can only be purchased through the insurance company, which typically won't authorize it until 90 days post-op). In February I got my Coagucheck and quickly discovered that it was reporting INRs about 0.7 higher than the Coagsense. I did multiple runs where I checked the Coagsense, the Coagucheck, and then went to the lab and got my blood drawn, all within 30 minutes of each other. The Coagucheck gave me the same result, or within 0.1, of the lab, whereas the Coagsense was 0.5-0.8 lower every time.
I called Coagsense and after much back and forth, verifying that my technique was correct, etc, they agreed to take my machine back and look at it. A few days after they received it, their VP of Clinical Operations called me. She explained how they cross-checked my machine with several other test machines in their lab, and other than failing to record one very elevated INR accurately, they found no issues. She explained in great detail how she stood by their technology and how she felt it was superior to other testing options. She offered to send me a new machine, so I agreed. The new machine had the same issues (and I used different lots of strips as well to ensure it wasn't a lot/test strip issue).
I had to spend a few weeks adjusting my warfarin dose to my "new" INR, as I had been basing the dose on the Coagsense recordings for over 3 months. I agree with you Protime, I'd rather the Coagsense underestimate the INR rather than overestimate it. But I have stopped using it. Not only is the Coagucheck consistent with the lab values, but I find it easier to use. I will use the Coagsense as an emergency backup in the event something happens to my Coagucheck machine, and I'll periodically test on it to ensure it's readings are still 0.5-0.8 behind the Coagucheck that way I know how to interpret it in case I need it. Otherwise, it's been relegated to the sidelines for me.
 

BluesCards

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I only have one meter, the coagsense which I bought myself two months after my surgery. I wanted full control over my testing, and did several lab draws to compare to my meter. I have mentioned this before, they were within .1 of each other. I feel good with that.
Protimenow - I know you have posted numerous times about the issues with this meter, etc. How maybe there is something in your blood that does not work with the coagsense.
I get it.
For me, it is my only option. I only have 1 arm for lab draws, there is no Coumadin clinic near me, Lab draws waste over 1 1/2 hours each time I do one as there are no appts. I did them in the beginning while waiting for my meter.
To go through a service, it was way to expensive. This is my only option. I get strips once a year, no script from the doctor is needed. My meter seems to be working fine. I will get a lab draw the next time I need bloodwork to compare.
I have called Coagsense customer service when I had a strip issue and wasted 4 strips. They were very nice and send me 6 as a replacement.

I just wanted to share my experience as some of us don't have many options. I don't like buying stuff off Ebay, to risky.
 

pellicle

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For me, it is my only option.
you're in luck ... no it isn't!

Go to eBay and get a Coagucheck for under $100 while they are still in the process of swapping out machines to the new INRatio. You can get your strips there too.

a number of members have done exactly this and are having excellent results (@Chuck C , @Timmay et al, personal communications, various posts here)

I don't like buying stuff off Ebay, to risky.
well you're just hobbling yourself with biases which don't stand up to actual investigation, so that's your choice. However if you get past that you do actually have other options. Personally I've been buying from eBay for 2 decades and quite frankly its the only way I can get what I need at all in some cases. I've had such a puny amount of issues and bottom line is in every case I've had satisfactory response from eBay and their Buyer Protection.

Best Wishes
 

Timmay

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@BluesCards - I purchased my CoaguChek XS on EBay. I purchased another CoaguChek XS on EBay to have a backup meter. Both work flawlessly and agree with each other. EBay has buyer protection. You can get your money back. Plus, the sellers are long-time sellers and have high ratings. They even guarantee the meter.

I’m the guy that would always buy new. This is the first time that I’ve bought such an important device used. I wouldn’t do it any other way. $290 for two completely functional devices. It was SUCH a success that I found two more for $29.99 each. Picked those up simply because Why Not? And one of these still has the plastic on the screen! Both meters only had like 15 readings. That’s it.

Roche is converting over to the newer device as pellicle said. Thus, these are becoming available at great prices.

Don’t shun eBay when it comes to the CoaguChek XS. So long as it’s a reputable seller there really isn’t any risk.
 

Protimenow

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Aside from the CoagSense meter, , that the manufacturer sent me a few years ago, and an InRatio that the manufacturer sent me because the other underreported my INR and caused a stroke, I've bought all my meters and supplies on eBay.

I got one set of Coag-Sense strips that didn't work at all, and I got a refund from the seller.

I've also bought two CoaguChek meters for $29.95 - the vendor apparently has hundreds - and both agreed with my original meter.

When I first started using Coag-Sense AND Coaguchek XS, both reported values just a few points apart - and labs were often the average of the two. Over the years, the gap has widened. Most of the times, the labs are closer to the XS than they are to the Coag-Sense. Once in a while, the value is closer to the Coag-Sense.

The XS IS easier to use than the Coag-Sense - but not by much. I just tested on both meters, almost simultaneously (within the same minute) using blood from the same incision - I got a big drop of blood, touched it to the XS strip so that it got enough to run a test, and encouraged the blood in the fingertip to fill the Coag-Sense transfer tube. As expected, the results are about 1 apart.

I don't know why - I suspect that, possibly, Coagusense (the name of the manufacturer) does something different when it calibrates the correction values for its strips.

The Coag-Sense does give me a bit more sense of security that my INR is NOT too low. I've recently purchased strips that expire about a year from now, and might consider testing with both meters (hey, it's an incision or two - a few drops of blood) for a while to see if the trend continues.

I will get a blood draw eventually.


If you CAN'T easily get to a lab, as others have, I encourage you to get one of the $29.95 meters. It may take a bit of tweaking of the strip guide to get it to run a test (a small piece of plastic - maybe the back of a used strip to raise the switch - should be all you need to get a meter that may even be new to work.

Roche's new meter has bells and whistles - Bluetooth, a color display, probably more memory - but uses the same technology and the same strips as the XS.

Don't fear eBay for meters and strips - look at seller ratings - look for free returns - and give it a try.

A lot of us have.
 

Protimenow

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Thought I'd mention that I too have had the same experience with the Coagsense vs. the Coagucheck. I bought the Coagsense before my surgery this past November as I wanted a system already in place when I got home (in the US, the Coagucheck can only be purchased through the insurance company, which typically won't authorize it until 90 days post-op). In February I got my Coagucheck and quickly discovered that it was reporting INRs about 0.7 higher than the Coagsense. I did multiple runs where I checked the Coagsense, the Coagucheck, and then went to the lab and got my blood drawn, all within 30 minutes of each other. The Coagucheck gave me the same result, or within 0.1, of the lab, whereas the Coagsense was 0.5-0.8 lower every time.
I called Coagsense and after much back and forth, verifying that my technique was correct, etc, they agreed to take my machine back and look at it. A few days after they received it, their VP of Clinical Operations called me. She explained how they cross-checked my machine with several other test machines in their lab, and other than failing to record one very elevated INR accurately, they found no issues. She explained in great detail how she stood by their technology and how she felt it was superior to other testing options. She offered to send me a new machine, so I agreed. The new machine had the same issues (and I used different lots of strips as well to ensure it wasn't a lot/test strip issue).
I had to spend a few weeks adjusting my warfarin dose to my "new" INR, as I had been basing the dose on the Coagsense recordings for over 3 months. I agree with you Protime, I'd rather the Coagsense underestimate the INR rather than overestimate it. But I have stopped using it. Not only is the Coagucheck consistent with the lab values, but I find it easier to use. I will use the Coagsense as an emergency backup in the event something happens to my Coagucheck machine, and I'll periodically test on it to ensure it's readings are still 0.5-0.8 behind the Coagucheck that way I know how to interpret it in case I need it. Otherwise, it's been relegated to the sidelines for me.
The former president of Coagusense told me that some clinics (maybe he said hospitals) use Coag-Sense meters to validate INRs over 4.0. I don't think he mentioned what happened with low readings.
The XS is notorious for deviations from lab results as the INR rises. For example (and this is off the top of my head, so the numbers may not be right), a lab value of 3.6 may show up as 3.9 on the XS. Perhaps the Coag-Sense is closer to lab values than the XS when the actual INRs go above 3.5 or so.
The former president has been gone from the company for a few years - I don't know if his earlier statement still applies. I don't know how many hospitals or clinics use the Coag-Sense to validate high INRs.

Finally - in a weird way, both meters might be accurate:

The International Standards Organization (ISO) has said that an INR can be considered accurate if the result is within +/- 20% of the actual value. My result from this afternoon was 2.3 on the Coag-Sense, and 3.4 on the XS. If you assume that the XS is actually closer to the lab value (and the lab value is +/- 20% of the accurate value), 20% less than 3.4 is around 2.7. Now, considering the value of the Coag-Sense - 2.3 + 20% is also around 2.8. The two meters (CoaguChek XS - 20%, Coag-Sense + 20%) overlap).

In theory, either one can be accurate.

In the case of the Coag-Sense, I'm more comfortable with a lower result on my Coag-Sense because I can reasonably assume that a reported INR above 2 ACTUALLY means that my INR is above 2. In spite of this, I've been using the XS more than the Coag-Sense (because it seems to correlate to the labs more often).
 

pellicle

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The XS is notorious for deviations from lab results as the INR rises. For example (and this is off the top of my head, so the numbers may not be right), a lab value of 3.6 may show up as 3.9 on the XS.
while I wouldn't have chosen the word "notorious", this controlled study gave the following:

1659151683928.png

I'll leave it as an exersize for the reader to plot the rest.

I would wonder if you are not confusing the old and discontinued (for some years now) Coaguchek S ...

Either way its hard to make a case that in the dangerous end (the low end) its out by far and if you are using it prudently (or as I'd prefer to say sensibly) then given the "fuzziness" of the range of INR which causes harm at a target of 2.5 for a mech AV you are very unlikely to come to any significant harm caused by the meter.

IFF on the other hand you are over 4 rather than debate about "am I 4.2 or 4.3 or even 5 put that energy into making a correction because if you see 4 you know you're off target and need to do something about that.

Now this is Notorious
 
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carolinemc

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The former president of Coagusense told me that some clinics (maybe he said hospitals) use Coag-Sense meters to validate INRs over 4.0. I don't think he mentioned what happened with low readings.
The XS is notorious for deviations from lab results as the INR rises. For example (and this is off the top of my head, so the numbers may not be right), a lab value of 3.6 may show up as 3.9 on the XS. Perhaps the Coag-Sense is closer to lab values than the XS when the actual INRs go above 3.5 or so.
The former president has been gone from the company for a few years - I don't know if his earlier statement still applies. I don't know how many hospitals or clinics use the Coag-Sense to validate high INRs.

Finally - in a weird way, both meters might be accurate:

The International Standards Organization (ISO) has said that an INR can be considered accurate if the result is within +/- 20% of the actual value. My result from this afternoon was 2.3 on the Coag-Sense, and 3.4 on the XS. If you assume that the XS is actually closer to the lab value (and the lab value is +/- 20% of the accurate value), 20% less than 3.4 is around 2.7. Now, considering the value of the Coag-Sense - 2.3 + 20% is also around 2.8. The two meters (CoaguChek XS - 20%, Coag-Sense + 20%) overlap).

In theory, either one can be accurate.

In the case of the Coag-Sense, I'm more comfortable with a lower result on my Coag-Sense because I can reasonably assume that a reported INR above 2 ACTUALLY means that my INR is above 2. In spite of this, I've been using the XS more than the Coag-Sense (because it seems to correlate to the labs more often).
My hospital lab uses coag-sense.
 

Protimenow

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while I wouldn't have chosen the word "notorious", this controlled study gave the following:

View attachment 888706
I'll leave it as an exersize for the reader to plot the rest.

I would wonder if you are not confusing the old and discontinued (for some years now) Coaguchek S ...

Either way its hard to make a case that in the dangerous end (the low end) its out by far and if you are using it prudently (or as I'd prefer to say sensibly) then given the "fuzziness" of the range of INR which causes harm at a target of 2.5 for a mech AV you are very unlikely to come to any significant harm caused by the meter.

IFF on the other hand you are over 4 rather than debate about "am I 4.2 or 4.3 or even 5 put that energy into making a correction because if you see 4 you know you're off target and need to do something about that.

Now this is Notorious


while I wouldn't have chosen the word "notorious", this controlled study gave the following:

View attachment 888706
I'll leave it as an exersize for the reader to plot the rest.

I would wonder if you are not confusing the old and discontinued (for some years now) Coaguchek S ...

Either way its hard to make a case that in the dangerous end (the low end) its out by far and if you are using it prudently (or as I'd prefer to say sensibly) then given the "fuzziness" of the range of INR which causes harm at a target of 2.5 for a mech AV you are very unlikely to come to any significant harm caused by the meter.

IFF on the other hand you are over 4 rather than debate about "am I 4.2 or 4.3 or even 5 put that energy into making a correction because if you see 4 you know you're off target and need to do something about that.

Now this is Notorious

I wasn't referring to the CoaguChek S.

Maybe notorious was the wrong word - something becomes notorious when enough people know it.
I don't know what Coag-Sense would say if my INR was close to 2.0 - if, or how much, different it will be from XS or lab.

I may skip a dose or two and bring my INR close to 2, and see what both meters tell me. If they agree when they're near 2.0, I won't worry about which meter I use - both will tell me when I'm out of danger -- the XS results will be higher than Coag-Sense, but it won't really matter to me AS LONG AS I am confident that my INR is above 2.
 

Protimenow

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My hospital lab uses coag-sense.
Interesting - but this sounds a bit odd.

All the hospitals that I've been to report INRs to a tenth of a point (even if this makes no practical sense). As far as I know, they use a 'tilt-table' for determining the INR. Of course, like Coag-Sense or XS, this requires that the reagent values are accurate.

XS and Coag-Sense strips have corrections built into the chip (on the XS) or the strip itself (with values somehow coming from the serial number of the lot of strips, or a scan code under the strip), or an NFC code that sets the meter to the current values for the batch of strips, to adjust to the reagent values.

Maybe your lab has more confidence in the rigor that Coag-Sense goes through to make sure the result is accurate than the lab is in the values for the reagents. Perhaps they want a standardized tool for determining INR.

Is this a large hospital? Is this a coagulation clinic associated with a hospital (they may use the Coag-Sense in the clinic because of its speed), but the hospital may use an arguably more accurate lab method.
 
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pellicle

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XS and Coag-Sense strips (supposedly) have corrections built into the chip (on the XS) or the strip itself (with values
AFAIK the data in the XS is the specific ISI value to apply to the time recorded (and thus calculate the INR). The code chip is matched to the strip and the strip data is printed on the strip top (and IIRC read by the machine).

1659391609962.png
 

carolinemc

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Interesting - but this sounds a bit odd.

All the hospitals that I've been to report INRs to a tenth of a point (even if this makes no practical sense). As far as I know, they use a 'tilt-table' for determining the INR. Of course, like Coag-Sense or XS, this requires that the reagent values are accurate.

XS and Coag-Sense strips (supposedly) have corrections built into the chip (on the XS) or the strip itself (with values somehow coming from the serial number of the lot of strips, or a scan code under the strip), to adjust to the reagent values.

Maybe your lab has more confidence in the rigor that Coag-Sense goes through to make sure the result is accurate than they are in the values for the reagents. Perhaps they want a standardized tool for determining INR.

Is this a large hospital? Is this a coagulation clinic associated with a hospital (they may use the Coag-Sense in the clinic because of its speed), but the hospital may use an arguably more accurate lab method.
Uh they use the same as you do, as they are up to date teaching hospital. Much better than getting a needle in the arm.
 

Protimenow

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AFAIK the data in the XS is the specific ISI value to apply to the time recorded (and thus calculate the INR). The code chip is matched to the strip and the strip data is printed on the strip top (and IIRC read by the machine).

View attachment 888713
They do. I wasn't disparaging the XS system - yes, a code chip tells the meter how to adjust the result, based on the value of the reagents in the strip. I have some doubts about the Coag-Sense strips, because results seem to always be lower than most labs, and certainly lower than those from the XS.
 

Protimenow

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Uh they use the same as you do, as they are up to date teaching hospital. Much better than getting a needle in the arm.
Yes, it is much better than getting a needle in the arm -- as long as the needle and the meter BOTH give accurate results.

I hope this lab occasionally takes blood from the arm and finger to compare results. (In fact, there may be no need for a finger prick if a drop of the blood in the tube is put onto the strip. (This only goes for standard tubes - some may have chemicals (citrates) that change the blood so it can't be tested with the Coag-Sense.
 

Protimenow

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Interesting - but this sounds a bit odd.

All the hospitals that I've been to report INRs to a tenth of a point (even if this makes no practical sense). As far as I know, they use a 'tilt-table' for determining the INR. Of course, like Coag-Sense or XS, this requires that the reagent values are accurate.

XS and Coag-Sense strips have corrections built into the chip (on the XS) or the strip itself (with values somehow coming from the serial number of the lot of strips, or a scan code under the strip), or an NFC code that sets the meter to the current values for the batch of strips, to adjust to the reagent values.

Maybe your lab has more confidence in the rigor that Coag-Sense goes through to make sure the result is accurate than the lab is in the values for the reagents. Perhaps they want a standardized tool for determining INR.

Is this a large hospital? Is this a coagulation clinic associated with a hospital (they may use the Coag-Sense in the clinic because of its speed), but the hospital may use an arguably more accurate lab method.
CarolineMC, I'm at a loss trying to understand why you hate this post.
Please clarify.
 
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