Hooray - I now have a Coaguchek XS

[Protimenow]

I was able to get a CoaguChek XS on eBay the other day at a price that I could handle. I also have six strips that arrived today.

I am surprised at how small the XS is. I'm pleased to see that the case can also hold the tube of strips. I will probably wait until Friday to run a test.

As some of you know, I am looking for the most accurate tool to determine my INR. Labs (some labs, at least) may not be all that trustworthy.

I have a lot of trust in my ProTime meter with the 5 channel cuvettes. I'm pretty sure that the Coag-Sense that I just got is also pretty accurate (though I don't always test with both meters, and when I did, the results weren't in agreement). I have a Hemochron - used in Operating Rooms, but I can't get the darned thing reset/unlocked so I can test to see if it passes the quality control tests).

Does this sound compulsive? Perhaps. I don't want another TIA (stroke), and want to be sure that my INR on the meter is accurate and IN RANGE. I'm recording results -- I have been for the four years that I've been testing - and I make my experience available to people who ask about it.

Right now, fortunately, I have a supply of strips (only six for the Coaguchek XS, but I hope to change that soon) for the Coag-Sense, the InRatio2 and the ProTime meters. I probably won't do four tests each week, but I will record the results on the meters that I do use. I may still have occasional blood draws, even though my coverage has run out.

It's clear that my the meters may respond somewhat differently to my blood than to blood from others (perhaps), and that my experiences may not always be the same as others. It's also probably true that the number of people who die because they trust inaccurate meters isn't known (or reported). However, for myself, I'm looking forward to comparing XS results with those from other meters and from the labs.

You can slam me for not trusting the meters and for getting more than one (when all I may actually need is one TRULY ACCURATE meter), but at this point, I still don't know exactly which to trust.

 

[chaconne]

Wow, you are quite the INR meter connoisseur. I must admit that I have the same tendencies myself. I have found it very interesting to read your posts and your experiences with all the different meters methods. Thanks for being willing to share it with us.

Blessings to you in your search for the "perfect meter"

 

[Protimenow]

Thanks for the encouragement.

It may be less than possible to find the 'perfect' meter, because there may not be a reliable standard to which I can relate the results. In some cases, being 'approximately' in Range may be the best I can hope for.

I have a Hemochron Jr, which is supposedly used in Operating Rooms (and is used at my anticoagulation clinic), so I assume that this may be the most accurate meter -- but, of course, it's a clinical device and there's no way for mere mortals to get support. I can buy the cuvettes (I think), but I can't unlock it so that I can use it. I need something called a 'Commander Cuvette' to unlock it -- unless I can get one from ITC, or perhaps the Anticoagulation clinic lets me use theirs, it'll probably remain unusable.

My goal for all of us here is to avoid the issues related to incorrect INRs - especially if these errors put us at risk of strokes or hemorrhages -- reporting some of my more relevant results may help move a bit closer to that goal.

My other goal--which I don't mind restating - is to help develop a system - or a world - where people who take anticoagulants can get tested - paying what they can afford (even if they can't afford to pay for the strips) - so that they can always stay in range. I went for a long time untested, and was very lucky NOT to have any negative events (other than what looked like a wart on my face that disappeared after I increased my warfarin). I don't want others to have to avoid testing just for financial reasons. From a public health standpoint, this doesn't make sense -- but to some financial systems, it's all about the dollar.

I will probably post results of my first Coaguchek XS test, against my Coag-Sense meter tomorrow or, if I can't wait any longer, later today.

Again - thanks for the encouragement and positive words.

 

[pellicle]

Hi

I for one will be interested to know your opinion on such areas as
* accuracy wrt vein draw cross reference
* comparative results between systems at the same time.
* ease of use (being one of the very few that has had such a cross section you are best placed to make usage / learning curve requirements comments)
* operating costs

You are in a relatively unique situation.

I look forward to you postings

 

[TheGymGuy]

I have Coaguchek XS and think its pretty accurate for me. I will be following this thread to see if you find any differences between readings from different meters.

 

[Protimenow]

Pellicle, thanks. I'm about to do almost what you're asking - if I don't run out of fingers first. I plan to test with the Coag-Sense and the Coaguchek XS. Later today, I may test with the InRatio (which I think is usually higher than the other machines and higher than the labs). I'm not sure about a Protime test or not.

In theory, if we 'learn' our meters and can adjust for any possible quirks (for example, if the InRatio is always .3-.6 higher than the labs, we can just subtract that difference to get a fair guess of the lab values and still stay in range), we should be able to manage our INRs (or let the so-called 'professionals' do it for us) and almost always be in range.

I'll update this thread after I've done some testing.

 

[Protimenow]

It's getting a bit confusing....

I tested with the Coaguchek XS first -- it is probably the easiest (and smallest) meter. I used a Unistik 3 Extra (which gets a big drop), and touched it to the side of the strip. The strip drew the blood into the strip, and I got a result fairly soon. Surprisingly, it gave me a 4.2 - which seemed quite high. (There may be some confounding factors -- I started the Coag-Sense, which was sitting next to the Coaguchek XS, and inserted a strip, and wonder if the small amount of vibration may have interfered with the test. I also MAY have taken a dose of Warfarin twice the night before last).

The Coag-Sense gave me a result of 3.5, with a prothrombin time of 41.9 seconds.

I though that I may also check on the InRatio - which has been .4-.6 higher than the Coag-Sense. It reported 4.1. My gut reaction -- I would probably trust the Coag-Sense -- a .6 difference from the Coag-Sense wasn't unexpected.

I've got a Protime 5-channel cuvette warming up. I will be testing with the Protime 3 in an hour or so to see what IT tells me.

FWIW -- the Coag-Sense works on directly detecting the formation of a clot (and, in theory may be the most accurate). The Protime meters also use a form of direct clot detection. The other meters use indirect methods to detect clot formation. Intuitively, it seems as if a direct measurement would be most accurate -- but who knows?

I'll post my Protime reading in an hour or two. (I may also call Roche about this used meter. Quality Control was fine, but ......?)

 

[Protimenow]

Curiouser and curiouser, to quote Lewis Carroll (Charles Lutdwidge Dodson).
I just ran the test with my Protime 3, using the 5 channel cuvettes. This gave me an INR of 3.2, with a prothrombin time of 41.8 seconds. The Coag-Sense gave me a Prothrombin time of 41.9 seconds, and the InRatio gave me a prothrombin time of 41.4 seconds. The Coaguchek XS doesn't give prothrombin times, apparently. It looks as if they're all detecting the clot within a few tenths of a second of each other. I wonder if their reagent values may not be quite as accurate as they should be. (INR is, after all, International Normalized Ratio - a ratio that is taken by dividing prothrombin time by a value for the reagent (I forgot the term for this, temporarily)).

What I'm concluding from this - other than the fact that each meter gave me a different number and, according to Roche, I 'shouldn't be comparing my INR to other meters', this range of a full 1.0 between the low of the Protime 3 and the high of the Coaguchek XS can be a bit troublesome. The XS is the easiest to use. It's the smallest. In this case, it is possibly the least accurate, in spite of what their literature claims.

I'm considering that my INR is at the high end of my range -- as reported by the Protime and the Coag-Sense. The prothrombin times are virtually identical. I will not change my diet or my dose because of these results.

I will probably test again, in a week (if not sooner), and see if the results converge a bit better.

(As far as ease of use - the Coaguchek XS is probably the easiest. The InRatio is fairly easy -- but it's often a pain trying to get the drop of blood on that small dot on the strip. The Coag-Sense, although it's a larger meter than the other two, isn't that difficult once you've gone through a short learning curve. It's designed to make it easy to get the drop of blood into a pipette and onto the strip and uses a method that may be one of the most accurate. The Protime is probably the largest of the bunch. It takes a lot more blood and can be a bit of a pain to get enough blood to run a test. It may be about equal to the Coag-Sense in accuracy but is a bit more difficult to use and may have a bit steeper learning curve. It will probably be a long time until I can get a blood draw to see what the lab values are, so I will probably use one or more meters for a while (I have the strips) and compare results. As long as I am comfortable that I'm not out of range (and at the high end of my range), I should be okay.)

I'm not sure if this information is very helpful, but that's what I've got so far.

(If I can figure out how to reset a Hemochron, this may be the best choice for accuracy -- but it's certainly not readily available. It may be a good standard against which the other meters are compared, but I don't know if I can finally get it unlocked)

 

[pellicle]

Hi

I didn't see the INR for the coaguchek,i I miss it or did you miss reporting it?

I only ever concern myself with INR and that is all the medical people use in vein testing over here for dosing.

I am unsurprised that there are different results. These are not perfect machines and what is perfect anyway?

 

[TheGymGuy]

Coaguchek XS gave him a 4.2.

Surprisingly, it gave me a 4.2 - which seemed quite high.

What is interesting is that pro-time for all the meters was around 4.19, and when I was comparing my INR to Pro-time it was basically a multipler of 10. When I had a blood draw and used Coaguchek XS within minutes of blood draw it was off by .1, it was .1 higher. I can try it again when I get my next blood draw.

 

[pellicle]

Thanks GymGuy ... I see it was in the earlier post ... which I didn't spot

 

[pellicle]

Hi

It's getting a bit confusing....

well ... perhaps also

Curiouser and curiouser

To quote from The Hunting of the Snark:

The Beaver had counted with scrupulous care,
Attending to every word:
But it fairly lost heart, and outgrabe in despair,
When the third repetition occurred.

Firstly let me say thanks for putting all this data together. I am sure it is a valuable resource for others who may be choosing a machine to buy.

So perhaps a summary is in order ... please correct me if I'm wrong but I read the above posts (now that GymGuy has put me straight thanks for that ;-) as:

Coaguchek XS = 4.1
Coagu-Sence = 3.5
InRatio = 4.1
Protime 3 = 3.2

To clear things up, did you test all on the same day?

to me these results are all quite close. If you assume that no meter is perfect then they have an average of 3.75. There are of course confounding factors with individual persons blood differences which some users such as PEM have highlighted so this needs considered when weighing the accuracy of each.

My feeling is that you'll likely be somewhere around 4.

what does this mean:

It looks as if they're all detecting the clot within a few tenths of a second of each other.

does it mean that you are saying that all machines take about the same time to make the assessment? If so, don't think that's an observation which has any bearing on the readings (at least in the case of the CoaguchekXS) as my understanding was that the tests took an amount of time and it is unreliable to assume that they are all operating by timing the duration to clot formation. The exception to this may be the one you have with the little spinning wheel.

I don't really understand this sentence:

What I'm concluding from this - other than the fact that each meter gave me a different number and, according to Roche, I 'shouldn't be comparing my INR to other meters', this range of a full 1.0 between the low of the Protime 3 and the high of the Coaguchek XS can be a bit troublesome.

Just what are you concluding from this? There were too many sub clauses and so I wonder if you are concluding that comparing results is difficult?

I can say that in my experience in electronics that if you have 1 meter you know the value: if you have 2 meters you are unsure of the value. I have never seen two meters agree perfectly. I am quite sure that counting frequencies or measuring voltages is a much more precise science than measuring INR, so some variance between instruments is to be expected. Especially when methodology varies.

I'm considering that my INR is at the high end of my range -- as reported by the Protime and the Coag-Sense. The prothrombin times are virtually identical. I will not change my diet or my dose because of these results.

my reading was that the Coaguchek XS and the InRatio were identical ... so have I got the data mixed up?

Lastly a simple table of results may be better to start with, then discussion. Its difficult reading through so much text to pick out the values.

Thanks for all your work

 

[Freddie]

and wonder if the small amount of vibration may have interfered with the test. I also MAY have taken a dose of Warfarin twice the night before last).

When in doubt do it again. Any vibration will disrupt the process.

FWIW: I have done a five year comparison with the Coaguchek XS with a vein draw - the difference is .2. And knowing that lab technicians here in Canada are allowed a .2 variance(+/-) when they conduct their tests.

Ask your lab technicians what their allowed variance is, then justify your findings with your monitor(s)

 

[Protimenow]

Some answers:

I did the initial test with the Coaguchek XS (4.2) and the Coag-Sense (3.5) within a minute or two of each other. The InRatio was tested about five minutes later - 4.1. The Protime test was about 2 hours later (these strips have to warm up before you use them). At Freddie's suggestion, I repeated the test 12 hours later, with the meter on a more solid surface and NO vibrations to interfere with the meter. This time the Coaguchek XS gave me a 4.1. I didn't retest with the other meters. The XS demonstrated, based on these two tests, that it's consistent.

As far as ease of use -- the Coaguchek XS seems to be at the top of the heap. The meter turns on when you insert a strip, and it is easy to get the blood ONTO the strip -- just touch it to either side of the strip or put a drop onto the strip. The InRatio, by comparison, provides a small target that, for me, was not always easy to hit. The Coag-Sense is considerably larger than the InRatio and Coaguchek XS. Once learned, the meter is pretty easy to use -- a collection device (minipipette or transfer tube) is used to take the blood drop off the finger, and put it into the collection area of the strip.

The Protime 3 is also large. I was told by a medical instrument dealer that the Protime with the 5 channel cuvettes is the most accurate. I JUST DON'T KNOW. It seems as if the monitors that actually give a result when a clot forms and breaks a beam of light clustered in the lower end (3.2, 3.5) and the ones that use impedance or amperage as an indicator (InRatio and Coaguchek XS) were in a higher range (4.1, 4.2).

One thing that I don't really want to think about is the meter's sensitivity to hematocrit and other blood factors. The Protime and Coag-sense are supposedly not sensitive to many blood issues that can alter the results reported by the other meters (I think). When I get medical insurance (oh, to live in Canada (?)), I can get a blood panel taken to see if the differences between the meters may be due to something that is KNOWN to have an impact on the results. (OTOH, all meters passed quality control tests with no issues).

I am certainly not looking for perfect agreement. I have an InrRatio and InRatio 2, and they don't always agree (I don't compare them to each other any more). It would be a bit more comforting if all meters came in reasonably close to each other. A 3.2 on my Protime and a 4.2 on a Coaguchek XS only tells me that the methods or results between the two can be considerably different from each other, and that I may have actually taken more than one dose two nights earlier. I may retest with one meter or the other in a few days, assuming that if I actually double dosed myself, the INR would progressively drop to my more usual levels in a few days.

 

[pellicle]

protimenow

Thanks for the information and clarifications. Very good work and its fortunate to have someone such as yourself able to do these tests.

I guess that the only remaining thing to do is get a vein sample and see how that goes for you. I would be taking the opportunity to retest with the machines when next you get a lab draw. That will give you a figure that you can rely on to baseline the other samples against.

 

[Ola Thoresen]

Re: Hooray - I now have a Coaguchek XS

I have used the Coagucheck XS since my operation in January, and tested it minutes after the lab test every time I have had one (at least once a week until recently).

Every time it has been within .1 of the lab results. I am sure this can vary from person to person, but for me it seems accurate.

 

[Protimenow]

Pellicle:

I sort of have baselines for the InRatio against labs, and a few against the Protime meter, going back almost a year. I don't know when I'll have another blood draw.

I did two more tests in the last 24 hours -- one was last night, because of a post about vibration skewing results. Last night, I put the meter on a more stable surface, and was careful to avoid any vibration -- my INR was 4.1. (It was 4.2 about 12 hours earlier).

Just now - 6 PM - I was demonstrating the XS to my daughter, who is a nurse , and the meter gave me a 3.4. What I'm concluding from this is that I probably DID take two doses two (or was it three?) nights ago, and my INR yesterday was high, as a result of the extra dose. Today, with the effect of the extra dose being considerably less, my INR also reflects this.

I was thinking of testing again in a few days because my INR may have been high as a result of a possible extra dose -- at this point, I'll probably wait until Friday (my usual testing day) because my INR seems to have returned to what the clinics call a 'therapeutic' value.

As far as ease of use is concerned, the Coaguchek XS is by far the easiest meter to use. It turns on when you insert a strip. It asks you to confirm that the code on the bottle of strips matches the code on the chip in the meter, and it has been easy to deposit the drop of blood on the strip.

I'm looking forward to some more parallel testing of this meter against one or more of the others, and eventually against a lab.

 

[lance]

Ola
That's my experience exactly since 2004. I trust my XS over any lab, anytime.

Happy testing!

 

[Protimenow]

One thing that I didn't point out was the near agreement between the CoaguChek XS and the InRatio 2 on multiple tests. I finally learned that using the Unistik 3 lancing device (for me, anyway) produced a large enough drop that it is adequate for the InRatio (and InRatio 2), the CoaguChek XS, and even the Coag-Sense meters. Although I have a LOT of 21 gauge lancets, it seems that the commercial lancing device (and I'm NOT suggesting one over any others) DOES make a somewhat larger incision so that you can get a large enough drop on the strip. (Make sure that you're getting a lancing device designed for INR testing -- I don't think diabetic lancets will do the job for you).

So far, the CoaguChek XS and InRatio 2 are still reporting slightly higher values than the Coag-Chek and ProTime 3 meters. (My last test: CoaguChek XS - 2.3, InRatio 2 2.4, Coag-Sense 1.8, Protime 3 2.0). This was low enough to get me to take a dose early, then to add another 1/2 dose at bedtime. I've slightly raised my dose - from 7.5/day to 8/day.

I'm about to test again with the CoaguChek XS to see if the slight increase in dosage has produced a result that is more comfortably in range.

I just checked -- the extra dose worked, and I'll stay at 8 mg/day -- I got an INR of 3.0 on the XS. I'm satisfied that I'm in range.

 

[pellicle]

Protime

have you tried the cotton thread / dental floss torniquet technique? I get great blood release fast this way, no "milking" and smaller incision needed. Only need to wind on about 3 or 4 turns of the thread and within seconds its showing signs of redness. Stab and a drop straight away.