A DIFFERENT Meter - Coagusense

[Protimenow]

No, there's no baseline, but these numbers are different enough to assume that one or two are just plain wrong. If so, then adding two incorrect values to one probably correct value would create an incorrect average.

If previous history is a factor, you may be correct, and the lab value will fall into place somewhere between the 2.2 and the 2.7 -- I wouldn't be particularly surprised to see a value of 2.45 (the lab for some reason thinks that it's accurate to 1/100 of a point). THIS, of course, would be pretty close to the average of the three meters.

Also - regarding the ProTime 3 -- the NiCad batteries in this meter are apparently failing -- although the meter was almost fully charged, the meter stopped during a test and gave a Battery Error message. Rather than plug the meter in and run it from AC power, I decided not to try again (although my irregular use of the meter will probably mean that the strips will expire before I get to use them).

 

[pellicle]

No, there's no baseline, but these numbers are different enough to assume that one or two are just plain wrong. If so, then adding two incorrect values to one probably correct value would create an incorrect average.

as a researcher its often a bad idea to make assumptions as to which data sets to 'drop' without good reasons.

I didn't have any good reasons so I averaged the data set to get a point of reference with which to compare. Equally the truth could be somewhere else, but in absence of knowledge its considered better practice.

wouldn't be particularly surprised to see a value of 2.45 (the lab for some reason thinks that it's accurate to 1/100 of a point). THIS, of course, would be pretty close to the average of the three meters.

they may be reporting just so as you don't have to wonder "which way did they round to 1 digit"

 

[Protimenow]

I am beginning to feel as if I'm slightly prophetic. I opined that my INR, as reported by the lab, would be almost mid-way between the Coag-Sense and the CoaguChek XS. It was - just slightly closer to the CoaguChek XS than to the Coag-Sense.

Here are the details from my blood draw last Wednesday and the home testing two hours later:

Lab: 2.52
Coag-Sense 2.2 (and, shortly later, 2.1)
CoaguChek XS 2.7
InRatio 2 3.0

Based solely on this blood draw, it appears that a) the Coag-Sense reports a value .3 (or .4) points BELOW the Blood Draw. The CoaguChek XS reports a value less than .2 ABOVE the Blood Draw. The InRatio 2 reported a value .48 above the blood draw.

ALL THREE meters reported within .5 of the Blood Draw. An average of the Coag-Sense and the CoaguChek XS appeared to very nearly match the Blood Draw (although a second test using the Coag-Sense, if averaged with the CoaguChek XS would have been .1 lower than the Blood Draw).

Historically, the Coag-Sense has been consistently below the CoaguChek XS (and the InRatio 2). As a person who had a TIA because I trusted a meter that was reporting higher than actual INR, I will probably feel safer with a reported INR of 2.0 coming from the Coag-Sense than I would with the same value coming from a CoaguChek XS, and if I had a 2.0 on the InRatio 2, I'd be scared enough to confirm with other meters and consider immediately taking a half dose.

So -- if I was asked, after all this, which meter I trust, I still wouldn't be quite sure. The method used by the Coag-Sense seems to potentially be the most accurate, because it detects a physical clot. It's also the meter that consistently reports the lowest INRs. Because I would personally prefer that my INR AVOID the bottom of my range, this is probably my meter of choice.

This isn't taking away from the probable accuracy of the CoaguChek XS. However, it seems to be reporting higher than the Blood Draw. If the XS reported an INR below 2.3 or so, I would begin to worry.

If it can be shown that the InRatio 2 CONSISTENTLY overestimated INR by a certain percentage (and if that percentage can be used to adjust the reported INR so that it matched the labs), this may also be acceptable. (It's kind of like a clock that's always five minutes fast -- if you know that subtracting five minutes from the clock will give you the correct time, it may be worth using that erroneous clock). There have been some proposed calculations that can bring the InRatio 2 scores into assumed Lab ranges -- I haven't tried these yet.

Pellicle: I'm looking forward to your response to all of this. The only good (?) standard that I have to compare to these meters is the one from last week - a 2.52 at the lab. My confidence in a meter that SEEMS to report lower than the labs is related to my bias towards having an INR that may be HIGHER than the meter reports. This should help keep me away from a 2.0 - which is where I want my INR to stay.

 

[Protimenow]

I guess that in some ways, I'm putting my life where my mouth is.

I am again testing weekly. Unless my INR is low, and I feel compelled to make minor adjustments and daily confirmations that the INR has come back up, once a week should be fine.

Yesterday, I reported that my blood draw last week was midway between the reported INRs on the Coag-Sense and the CoaguChek XS. The Coag-Sense was consistently lower than the CoaguChek XS. With a lab value of 2.52, I didn't see any major difference (well, perhaps .5) between the Coag-Sense and the CoaguChek XS. The InRatio 2 has always been higher.

I've had a fair amount of wine this last week, and may also be fighting off a sinus infection (with no antibiotics yet), so I wasn't surprised that my INR is elevated. The wine that I've been drinking seems to almost consistently raise my INR (Sutter Creek Pink Moscato). Today, with my weekly test, here's what I got:

Coag-Sense: 3.4
CoaguChek XS: 4.3
CoaghChek XS: 4.5

I ran the test on the CoaguChek XS because I wanted to see if there was a difference in reported INR based on the amount of blood deposited on the strip. (There actually was - .2 - probably insignificant, but still interesting). The first two tests were, literally, done within seconds of each other. The second CoaguChek XS test was about ten minutes later, from a different finger. The difference between the Coag-Sense and the CoaguChek XS is more interesting, and not inconsistent with earlier tests. It is clear that as my INR goes up , the difference between Coag-Sense and CoaguChek XS also increased.

Whichever meter I'm using, it's clear that I'm either at the top of my range or above it. I'm not going to change my life because my INR is a bit high -- I'll probably keep away from the wine for a while, and may even take a multivitamin with a bit of Vitamin K in it.

What I may have to do the next time I am scheduled for a blood draw is to have some wine for a day or two before my blood draw, in the hopes that the INR on both meters will be elevated, and see what the lab reports.

For now, I'm going to assume that my INR is somewhere between 3.4 and 4.5 and live with those results. And, for now, I'm leaning towards the idea that the Coag-Sense is the more accurate of the two. Without a reliable blood test to confirm this, though, I'm still only guessing.

 

[pellicle]

Hi

sorry, I missed this earlier ...

Here are the details from my blood draw last Wednesday and the home testing two hours later:

Lab: 2.52
Coag-Sense 2.2 (and, shortly later, 2.1)
CoaguChek XS 2.7
InRatio 2 3.0

interesting numbers ... as you observe the lab is in the middle of the XS and the C-S readings.

Of course this is only one reading, so its a bit early to call "X Y or Z" as a result. Also knowing how the lab operates and what reagents they use will be interesting.

my view is that you have a range of data and all measurements fall into a broad band of result. If you prefer to keep your "target" at (say) 2.7 then in all cases you'll be inside a "range" of 2.2 ~ 3.5 ... personally I am happy if my measurement shows 2.7 and will consider toning down my dose (a bit) with 2 consecutive weekly readings of over 3.2

The only good (?) standard that I have to compare to these meters is the one from last week - a 2.52 at the lab. My confidence in a meter that SEEMS to report lower than the labs is related to my bias towards having an INR that may be HIGHER than the meter reports. This should help keep me away from a 2.0 - which is where I want my INR to stay.

I'd agree with that ... although I can't yet say I'm confident that the meters will always stay at those relative locations from the blood draw, but I feel that its likely you'll continue to get that sort of variance between them all....

 

[pellicle]

Hi

I've had a fair amount of wine this last week,

and you stated those previous results were from Fridays testing ... right?

[/QUOTE]and may also be fighting off a sinus infection (with no antibiotics yet), so I wasn't surprised that my INR is elevated. The wine that I've been drinking seems to almost consistently raise my INR (Sutter Creek Pink Moscato). Today, with my weekly test, here's what I got:

Coag-Sense: 3.4
CoaguChek XS: 4.3
CoaghChek XS: 4.5
[/QUOTE]

which is elevated, yet you said that you drank last week? This would seem to suggest to me that the wine decreases your INR (contributes to clotting).

(There actually was - .2 - probably insignificant, but still interesting). The first two tests were, literally, done within seconds of each other. The second CoaguChek XS test was about ten minutes later, from a different finger.

was there different technique? Different duration between incision and registration? Different "massage" of finger?

I'll probably keep away from the wine for a while, and may even take a multivitamin with a bit of Vitamin K in it.

but didn't that lower it?

also I understood that Broccoli had higher bioavailable vit K ... perhaps that would be good?

What I may have to do the next time I am scheduled for a blood draw is to have some wine for a day or two before my blood draw, in the hopes that the INR on both meters will be elevated, and see what the lab reports.

will be interesting to see if it makes any difference, but this sort of thing is hard to plan an experiment to determine.

thanks for all the reporting.

I missed a dose on monday night and have been doing daily testing to see what the results are

 

[Protimenow]

The results that I gave for the lab testing were for Wednesday, June 26. That was the day that I was able to get a blood draw, so I used my meters about two hours after my blood was drawn.

These results were fairly consistent with the tests from two days earlier.

6/24/13

Coag-Sense: 2.5
XS: 2.8

6/26/13

Lab: 2.52
Coag-Sense: 2.2
XS: 2.7
InRatio 2: 3.0

For some reason, it seems as if the wine - in my body, at least - elevates my INR. One week later - also on a Wednesday - I had the elevated INRs, seen here:

7/3/13

Coag-Sense: 3.4
XS: 4.3
XS (bigger drop of blood) 4.5

When the INR on either meter is elevated, the distance between the values in the meters widens. It's been that way consistently.

I don't know for certain WHY my INR climbs - but it seems to be associated with this wine. Perhaps my liver has a problem with it, and too much alcohol impairs its ability to process Vitamin K (or something).

My testing technique for each meter has stayed consistent - first drop on strip within fifteen seconds of incision for all tests. I've used part of the big first drop for the XS and the Coag-Sense (with the XS getting the beginning of that first drop, and the Coag-Sense getting the blood a bit later, but still within fifteen seconds. If I wasn't down to my last two Coag-Sense strips, I would not try to reduce the number of finger sticks by splitting that drop between the meters, but would use a fresh drop from different fingers for each strip).

Your suggestion to eat broccoli is an interesting one. I'd rather eat a head of lettuce - or take low dose Vitamin K - of half dose of Warfarin one time - than to have to eat broccoli.

A time line relating to your INR and your missed dose would be interesting. Personally, I wouldn't change anything (and I doubt that you did) because of a single missed dose.

 

[Protimenow]

I am running low on Coag-Sense strips (I only have two left), and I don't think that I'll be able to get a new box of 50 for another week or two, but I still have quite a few CoaguChek XS strips. On Wednesday, July 10, my INR, as reported by the CoaguChek XS, was 3.9. This didn't worry me. I didn't change my warfarin dosage. From previous comparisons to the Coag-Sense, I'm comfortable in concluding that this other meter would report something close to 3.0 -- putting me in the middle of the range. However, if the CoaguChek XS was EXACTLY right, this slight elevation above range doesn't trouble me.

(Interestingly, I have probably about 60 InRatio strips, but I'm not usually testing with it because the values always seem to be quite a bit higher than lab or Coag-Sense. I may do a test today - primarily because I still have ten digits and I have a lot of strips - but don't expect to see a reported INR BELOW 3.8 or so. I don't think that my INR would have changed much since two days ago. IF the InRatio surprises me with a low value, I may come back to this thread and report it. Also -- if anyone out there is interested in buying some of my InRatio strips, send me a Private Message -- I'm sure that we can work something out)

 

[Protimenow]

One more entry in the continuing Coag-Sense saga:

I tested my INR yesterday (7/18/13), using the Coag-Sense and the CoaguChek XS.

Coag-Sense: 3.1, PTT 37.3
CoaguChek XS: 4.2

I'm not sure that I got a large enough drop on the XS strip, but it passed the strip's internal quality control test and provided a result, so I guess that the test was okay. I may do a test today (a day later) with my InRatio 2. The tests that I made yesterday were done within a minute of each other, using different fingers.

A 3.1 (or even a 4.2) don't bother me much. With either result, it appears that I'm at the upper end of my range - where I'd prefer to be, anyway. I may have an extra piece of lettuce on a burger, or have some other palatable source of Vitamin K, but I don't plan to make any changes. If my INR is similarly high next week, I may CONSIDER something to lower my INR.

I've been able to get another 50 Coag-Sense strips that should arrive in a week or so. I'll probably be running parallel tests with Coag-Sense and CoaguChek XS. I expect that I will probably always see a difference -- with the CoaguChek XS higher than the Coag-Sense -- and I can accept this. I also expect the difference to broaden as the INR increases. (In other words, the closer my actual INR gets to 2.0, the closer the results on both meters are -- the closer my INR gets to 3.5, the further apart their results become)

If the XS ever reports an INR that is high enough to concern me, I may eventually try to get a prescription for a lab 'confirmation.'

 

[Protimenow]

These meters continue to not surprise me. I just posted yesterday's test results. A few minutes ago, I ran a test with my InRatio 2, using a strip that expired last month. InRatio meters don't seem to have a problem with recently expired strips.

The InRatio gave me an INR of 4.2, with a Prothrombin time of 43.7 seconds. It's been nearly 24 hours since my previous tests, so it's not necessarily accurate to compare results that far apart. However, the 4.4 on the InRatio 2 and the 4.2 on the CoaguChek XS seem to parallel similar 'closeness' of values reported by the two meters. The amount of difference from the Coag-Sense also seems fairly consistent with the results of the InRatio 2 and CoaguChek XS.

Doing as Pellicle would probably do, my 'actual' INR may be an average of 3.65 (using Coag-Sense and CoaguChek XS results), or 3.9 (using the results from all three meters). At worst, I'm thinking that my INR may be around the top end of my range (2.5-3.5). Even if it was actually slightly above 4.0, I don't think that I would do much differently. I'd rather take the risk of having an INR of slightly higher than range - and be careful about bumping into things - than to be below range and at risk of stroke.

 

[pellicle]

I'm not sure that I got a large enough drop on the XS strip, but it passed the strip's internal quality control test and provided a result, so I guess that the test was okay. I may do a test today (a day later) with my InRatio 2. The tests that I made yesterday were done within a minute of each other, using different fingers.
...
If the XS ever reports an INR that is high enough to concern me, I may eventually try to get a prescription for a lab 'confirmation.'

Personally I find that there is little if any difference. The main differences I found on the coaguchek came from incision /extraction technique.

 

[Protimenow]

I'm not entirely sure which differences you refer to. The CoaguChek XS and InRatio 2 seem to be very close. However, a 3.1 on the Coag-Sense and a 4.2 on the CoaguChek XS IS a difference. Theoretically, both are only about .5 apart from a mean value -- but some medical 'professionals' would react to a 4.2 (or the InRatio 2's 4.4) by changing weekly dosage. I didn't repeat the test using the XS, basically because the QC on the strip said that there was enough blood for a test. Although I'm fortunate enough to have a still fair supply of strips, I'd prefer not to fly through them.

What the three tests in the last two days have told me is basically what I want to see:

My INR is above 2.0
My INR is possibly in range
My INR isn't high enough for me to make any drastic changes

----

I should have a new batch of Coag-Sense strips next week. I'll run a quality control test on two of the control test strips that come with the batch of Coag-Sense strips in order to verify their accuracy. I'll use the last strip from my current supply and probably compare it to the XS and InRatio 2. I'm not sure if I get a blood draw in the next week or two - but I DO see an Anticoagulation clinic on July 31. They may test me with the Hemochron that they have in their clinic, rather than running a blood draw.

I'll probably report these values, too.

 

[pellicle]

I'm not entirely sure which differences you refer
o.

Between blood draws and the coaguchek values and between drop sizes and coaguchek reporting of INR

 

[Protimenow]

I've changed my testing methods slightly since the last many tests comparing the Coag-Sense and the other meters. Previously, I was using the 'same' drop of blood (blood from a single incision) for the Coag-Sense and the CoaguChek XS, in order to spare me from an extra incision. I finally wondered if the delay between the XS and the Coag-Sense drop may have had an impact on the Coag-Sense results.

This morning, I did a separate test, being sure to use the blood for each test within fifteen seconds of incision. Here are my results:

Coag-Sense: 3.0
CoaguChek XS: 3.3

I'm a lot more comfortable with this comparison between meters than I was previously. The XS is still slightly higher than the Coag-Sense, but this is well within acceptable range. (A test a few hours later, using an InRatio 2, was strangely high - 4.8 - but may be due to a collection issue)

-----

It may be possible that my older procedure - CoaguChek XS followed by Coag-Sense may have yielded a lower INR with the Coag-Sense because the blood had already started to clot before the Coag-Sense got it. I am not sure that this is the case, though, because when I repeated tests using the Coag-Sense and a clean incision, the results were still very close to the initial Coag-Sense results. I have a new stock of strips, so I'll again report on some comparison testing in the future.

 

[pellicle]

Hi

Previously, I was using the 'same' drop of blood (blood from a single incision) for the Coag-Sense and the CoaguChek XS, in order to spare me from an extra incision. I finally wondered if the delay between the XS and the Coag-Sense drop may have had an impact on the Coag-Sense results.

I thought I had mentioned this, and wondered if you were breaking the 15 second rule ...

 

[Protimenow]

I'm very aware of that fifteen second rule - and I think that both transfers took place within the fifteen seconds. What I didn't think too much about was that the very first fluid (aka blood) that comes out of the incision may be slightly different in composition than the few microliters that come behind it. So, even though the transfer may be done within fifteen seconds of incision, the blood that I got AFTER that first few microliters that I put on the CoaguChek XS strip was slightly different than the blood that went onto the Coag-Sense -- and this was enough to make a difference. (Logically, though, it would seem that the very first blood would tend to clot more rapidly than the later bit of blood, which had fewer of the clotting factors, so my INR should have been LOWER, rather than higher, on the tests that I ran with the XS).

Also, although the other blood may have been transferred within the fifteen second period, the second portion of blood may have already started clotting. This would, of course, result in a lower INR than the initial sample that was transferred to the XS strip. I won't spare fingers from here forward--a separate finger for each meter, even if I can get blood from one incision onto two meters within the fifteen seconds.

I realize that I may be the only one here who cares about using more than one meter for testing, but I'm really concerned about testing accurately and, perhaps, finding the most accurate meter.

 

[Protimenow]

OUCH, in advance.

Tomorrow, I'm going to the Anticoagulation Clinic. They didn't order a blood draw, and don't seem to want me to have one. Instead, I'll be tested with the lab's Hemochron meter. (This is a hole in Finger One). At home, before I go to the clinic (probably), I'll test using my Coag-Sense and another finger (finger #2), and also run a test with the CoaguChek XS (finger #3). I may do a fourth finger, later, using the InRatio.

I'll report my results some time tomorrow.

 

[RobThatsMe]

Hi PTN,

I have two suggestions. I usually take my home testing unit to the lab with me when I want to check it against the lab. They have no issue with me testing right after they do theirs. See if that may be a possibility for you.

Also, I am a member of two hospital private web sites that I frequent. One of which is a large multi- facility operation, that includes hospitals, doctors and labs.
I can go on the site and e-mail my doctors, this give me real quick replies.
Also, any labs that are done, are immediately available to me on the site once they process the results in the lab. I actually get to view them just as quickly as the doctor. You may want to check into this feature at your hospital of clinic, if it is affiliated with a larger hospital group.

With all these testing units, and analysis, you may soon become a human pin cushion. <smile> Thanks for such detail comparisons to the home testing units!

Rob

 

[Protimenow]

Rob:

Thanks for the suggestions.

Unfortunately, the clinic where I am 'managed' is one that seems to assume that all of its clients are indigent, unemployed, with sub-average intelligence, who are doing all that they can to be able to figure out where the hospital is located and where to go to keep an appointment. They told me that I can bring in a meter -- but that they'll take it from me and send it from their lab to check its accuracy. I'm concerned that if I bring a meter, they'll try to take it from me (even if it IS mine). I don't really want to leave a meter in my car. I figure that an INR taken minutes before I go to the clinic (probably 30-45 minutes before they test my blood) will give me results that should be pretty close to what the clinic finds. Today, they will be testing with a Hemochron - a meter that is being used during operations to assess INR and other blood values.

Although this hospital is a training hospital for UCLA, I don't know that I can get into a group or find a private web site where I can actually view my results. I'll see if the hospital has such a site -- it would certainly make things a lot more transparent for me.

In the past, the clinic didn't think it important that I get the results of blood draws if they were in range. I've had to call many times to get results of lab tests.

Yes, every week, my left hand gets a few punctures - one on each of two fingers, sometimes a second puncture on a finger (for the InRatio or ProTime) - but I still have my RIGHT hand. (I don't know which hand they'll use at the clinic -- maybe I'll do my home testing AFTER I go to the clinic so they don't see the fresh incisions on my fingers).

I'll continue to use my Coag-Sense and CoaguChek XS, and perhaps also compare to InRatio and ProTime. Occasional lab verifications would also be good. (FWIW - I have a Hemochron - but it came from a clinic and requires an unlock code so that it can be used -- for now, it's just a brick. If I'm ever able to get a Hemochron and supplies - and if it passes the QC testing that it requires, I plan to add this meter to my others.) This testing with multiple meters isn't just a manifestation of OCD -- I had a TIA last year and want to be sure that this does NOT happen again.

 

[RobThatsMe]

HI PTN,

Both of the hospitals I go to have their own patient websites, Vanderbilt and Cleveland Clinic.
They are also both training hospitals. You should look into yours, especially since it is a teaching hospital.

Rob