New Coag-Sense meter

[Protimenow]

I'm not sure how many visit this site, or how often, but I'd like to say that Coag-Sense (my most trusted meter) has just received FDA approval for a new meter - the PT2. It's more compact than the meter that I've been using for years, and has many new features that seem to put it ahead of other meters available in the United States.
I haven't gotten my hands on one, but the coag-sense website has posted information about it (coag-sense.com).

Once I've been able to do some testing with it, I'll probably post a review--if there's anyone out there who wants to learn more about this new meter.

I may watch for replies.

 

[LondonAndy]

Definitely interested, though I am not sure the Coag-Sense is available in the UK. I have only ever used a CoaguChek XS, which they have now replaced with the CoaguChek Inrange, which again is INR only.

 

[Protimenow]

I don't know about CoagSense outside the United States. You can get more information on the CoagSense site - coagusense.com, coag-sense.com. I now have the new model - CoagSense PT2. It's probably the most advanced PT/INR meter currently available (although I don't know a lot about the CoaguChek InRange). This new meter is compact. I don't have an InRange to compare it to. The CoagSense IS portable -- if I had any need to test while traveling, it would fit nicely in any carry on or traveling bag. The meter has WiFi, USB, Bluetooth, an Ethernet port, and an NFC reader. The NFC reader is used to scan the lot and barcode numbers from the bottom of a box of strips -- switch to a new box, and it's easy to accurately enter the codes. The ports are useful for reporting results and doing firmware upgrades. You can also attach a proprietary printer or barcode scanner. (These features should make the meter attractive to clinics, hospitals, doctors' offices, and other locations that use the meters). A color display helps guide you through testing and setting the meter up. Results can be viewed in a chart, or the actual numbers. Each result shows the strip lot number, prothrombin time, INR, and time and date of the test. This new meter can hold 2000 results -- again, a feature that's good for professional offices (for self testers doing a test a week, we're looking at decades of stored results -- by the time you get anywhere NEAR that number, the lithium battery will be unusable, you may be able to check your INR with a small touch sensor, and global warming may have killed everyone off). The lithium battery that is built into the unit is charged with mini-usb and can do up to 200 tests. I like this meter. It takes a minute or two to start (as opposed to almost immediate start-up for the original meter), and it seems like almost fun to use. Tests aren't any faster (because it's still testing ACTUAL clotting time on either meter), but better memory storage, not having to face the 'replace batteries' message, color touchscreen display, and overall 'sexiness' make this my new favorite meter. For users and clinics in the United States, there seems to be an issue with current strips not being usable in the new PT2 meter, but I'm sure CoagSense will probably resolve this. I've tested many meters - from the original Protime, through InRatio 1 and 2, updated ProTime, CoaguChek S and XS, and the two CoagSense meters. I determined, years ago, that CoagSense compared most closely to blood draws of all the meters I've tested. This new meter just pushes the technology for professional testing and self testing to another level.

 

[LondonAndy]

I agree it is a sexy meter! I watched their video and it looks good as well as having some cool features. Just seems a bit more is involved for doing each test, transferring the blood via a sort of pipette whereas the CoaguCheck XS is a drop of blood directly to the test strip of course.

I am content with the XS meter's slightly less accurate readings which I don't consider significant to my treatment, but it is good to keep abreast of what else is coming onto the market for the day I am looking to replace it. No sign of that at 4 and a half years old so far, I am pleased to say.

 

[Protimenow]

Yes. It's a slight extra step. Instead of touching your finger to the XS strip, you touch the transfer tube to your finger, and it draws the drop of blood into the tube. The extra step: place the tube into the well on the strip and press the plunger. Yes, it's an extra step, but, to me, the accuracy is worth that extra step. (OTOH - if your drop of blood when you touch the side of the XS strip isn't adequate, the test fails, and you end up wasting a strip - with the Coag-Sense, you KNOW when enough blood has been collected, because you can SEE it in the transfer tube). Also - Coag-Sense strips are individually wrapped - there's no damaging other strips if you don't cap the tube holding the strips quickly or firmly enough.

Neither of the points above would probably motivate you to change meters. Because your XS is working for you, and you're comfortably in range, you'll probably want to stay with it.

 

[Thomas]

Since I'm in the middle of doing research on which system to purchase so I can start testing at home, could you or someone elaborate on the differences in accuracy between systems like the Coag-Sense and Coaguchek.

Also, is there a calibration option so that you can make adjustments to the home unit or at least know that there's a consistent discrepancy over a bit of time that you can rely on?
Thanks.
Thomas

 

[tom in MO]

Since I'm in the middle of doing research on which system to purchase so I can start testing at home, could you or someone elaborate on the differences in accuracy between systems like the Coag-Sense and Coaguchek.

Also, is there a calibration option so that you can make adjustments to the home unit or at least know that there's a consistent discrepancy over a bit of time that you can rely on?
Thanks.
Thomas

I believe that INR meters are self calibrating using materials on the disposable strip. That's why you don't need to send your meter back for "calibration" and you don't really need to compare your meter reading to a office blood draw...which could be read on a meter as well

 

[LondonAndy]

Hi Thomas. You will find many posts about the issues of measuring INR, particularly by Pellicle who has much more biology knowledge than I do. Here's my take as an amateur with about 4.5 years of experience of self testing.

I think it is a reasonable summary to say that CoaguChek XS readings are about +/- 0.2 of a well processed lab result from a blood draw taken at an anti-coagulation clinic. It seems from my own experience and comments by others here that the meter is more likely to show 0.2 BELOW a lab result. So if, like me, you are on a therapeutic range of 2.5 to 3.5, a result of 3.0 could be 2.8 or 3.2. I am content with that - it is sufficient for me to confirm I am comfortably in range and don't need to make any changes.

If the meter result was 2.7 then I would not be quite so happy, because that might mean the reading is really 2.5. I would increase my dose by 1mg or maybe 2mg for one day to get it closer to the centre of my therapeutic range.

Personally I am more concerned about low readings than high readings - I would not mind if a result was 3.6, for example, as for me, somebody who does not do activities such as contact sports or hiking that might give rise to injury and "bleed outs", a low INR is a greater risk of stroke.

There is no adjustment possible with the CoaguCheck XS. It is worth noting that in the UK this meter is the only one approved by our national regulator, and is seen as the "gold standard" of INR monitoring. See this report for details, and the massively better outcomes than less frequent testing at clinics.

 

[Thomas]

Thanks for the response gentlemen.
Since we're trying to stay within a range (2.5-3.5 with a target of 3.0 for me). It would seem that a result within .2 is a reasonable variation from a lab result. As you say L.A., higher is better. Assuming the manufacturers are striving for the most accurate and consistent readings possible, either of the two mentioned companies products would be good.
I know the CoaguChek line is offered in Canada. I'm not sure about the Coag-Sense. I haven't been able to find it locally online yet.

 

[pellicle]

Hi

Since we're trying to stay within a range (2.5-3.5 with a target of 3.0 for me). It would seem that a result within .2 is a reasonable variation from a lab result.

I would agree and think this is a very sound assessment. An important part of understanding INR is that its meaningless to consider differences of less than (say) 0.2 because 1) there just isn't sufficient accuracy in the system anywhere 2) it makes essentially no difference to you in outcomes of any kind.

Once you consider how the number is produced you need to delve into a world of reagents and chemistry and physical movement cessation determining that shows that this is no "Vernier Caliper" for measuring the thickness of steel here. Consider this document:

which makes it clear that depending on reagent used there will be quite some variation in readings.

Then there is the notion of "clinically significant difference" in obtained reading. For instance if your INR was 3.1 or 3.3 would that make any difference to your response to that reading? What if it was 3.9 or 4.1?


So my approach has been two fold: use the meter I have which was available to me and which has a good and convenient supply of strips. In my case this was the Roche (I'm Australian and its to my knowledge the only one on our market) and secondly to go to get a blood draw periodically to compare with it. That's typically 6months or yearly for me.

I don't know if you're self managing your dose (I have been for at least 7 years now) and have written up a few notes on my blog to assist any who find it.

http://cjeastwd.blogspot.com/2014/09/managing-my-inr.html

indeed you'll see a Label cloud on the left (unless using a phone which is a ****** internet experience anyway) where you can find topics under tags, everything I've written about INR is under the label of INR http://cjeastwd.blogspot.com/search/label/INR

It seems your already on the right path to me ;-)
Best Wishes

 

[Jamey T]

I did see that new meter, and I am considering it. I have to say, that when I find something that works well for me, I am a little resistant to change. My current CoagSense is very accurate for me so I am not in a hurry to buy the new one.

 

[Protimenow]

I have the new Coag-Sense meter. I really like it a lot. It seems to have the same accuracy as the original meter (it should, it uses the same physical method of detecting a clot, and the new strips can be used in the classic or the new machine).

The new meter is much smaller than the original. It has a color, touch panel screen, and many of the bells and whistles required by clinics, hospitals, and doctor's offices.

If I didn't have the new meter, the original would do just fine. For a self-tester a relative advantage of the old meter is that it starts up almost immediately - the new one makes you wait while the firmware is set up -- there's a lot more in the new meter than in the old one.

The new meter appears to have been designed for use in a clinical setting. It stores up to 2000 results. It has WiFi, USB, an NFC scanner, and a port for a bar code reader or a printer. The meter can record patient number, it can record operator number, it records strip lot number, it appears to have most, if not all, of the features that a clinic or doctor's office needs for INR testing.

The method of getting blood onto strip may actually be more effective for the Coag-Sense than the CoaguChek in a clinical environment. Here's why I say this:
With the CoaguChek, the finger is incised and the person running the test 'hopes' that the patient touches the edge or top of the strip with the drop of blood. This may be an issue for some people - especially those who haven't been tested before. The Coag-Sense puts the transfer into the hands of the clinician - or the self-tester. After the finger is incised, a transfer tube is touched to the blood drop. Capillary action draws the blood into the tube, the tip of the tube is inserted into the well on the strip, and a small plunger transfers the blood onto the strip. For self-testers, a bit of practice makes this easy. For clinics, putting this under the control of the clinician running the test should result in minimal test failures resulting from errors in getting blood onto strip.

In my testing a few years ago - in which I tested the Coag-Sense, CoaguChek XS, CoaguChek S (before it was discontinued), InRatio (dittto), Protime Classic and Protime3 against one or more clinical labs, I determined that the Coag-Sense was the most accurate, when compared to lab results. The CoaguChek XS that I tested gave higher than lab results when INRs were above 3.5 or so - with the spread between lab and meter increasing the higher INR became. The Coag-Sense either matched the lab results or was slightly lower than the lab results. (There were a few labs that I encountered along the way that mishandled the blood sample and came out with ridiculously high INRs that none of the meters came close to).

For a user who is new to self-testing, the new Coag-Sense meter is, based on experience with the meter, a very strong choice. I have doubts that, in the United States, at least, it would be difficult to find strips.

 

[maggiemay]

I agree it is a sexy meter! I watched their video and it looks good as well as having some cool features. Just seems a bit more is involved for doing each test, transferring the blood via a sort of pipette whereas the CoaguCheck XS is a drop of blood directly to the test strip of course.

I am content with the XS meter's slightly less accurate readings which I don't consider significant to my treatment, but it is good to keep abreast of what else is coming onto the market for the day I am looking to replace it. No sign of that at 4 and a half years old so far, I am pleased to say.

I have been self testing with the CoaguCheckXS monitor for 13 years, and touch wood it is still working and I have it compared to the clinic results on a six monthly check up. If it registers within 0.5 INR compared to clinic blood test I am assured by the hospital that it is reliable. I go today for the testing and to see that I am still able to do my self testing .

 

[vivekd]

MDINR provided me CoaguSense meter last year for home use. I used it for 3-4 months and personally it was a nightmare. It kept on giving me errors that I was producing air bubble with the blood deposit. Every week, i needed to test 4-5 times before getting the results. I worked with MDINR to switch to CoaguChek XS and have not experienced any testing failures since then.

 

[Protimenow]

When I first got my Coag-Sense, four or five (maybe more?) years ago, I had some initial issues with blood transfers and an occasional air bubble. Back then, they used a micropipette and a tiny syringe to draw the blood into the micropipette and then deposit it onto the strip. It took a few tries to get the sample without introducing air into it.

They followed with some transfer tubes -- touch the tip of the tube to the drop of blood, capillary action draws the blood into the tube, and you place the tip of the tube onto the spot on the strip and squeeze the top of the tube (covering the air hole), to dispense the blood onto the strip. I rarely had problems with this method. But, in some cases, if you squeeze the bulb too quickly, or don't completely cover the hole on the transfer tube (or don't push the tube into the spot on the strip where the blood is deposited), you can introduce air.

The newest transfer device is another small tube with a plunger at the top. If you follow the instructions correctly, you incise your finger, make sure you have an ample size drop of blood, then put the tip of the tube parallel to or slightly below the blood drop - then INTO the drop. The blood should flow into the transfer tube. Then, just put the tip of the tube into the well on the strip and slowly push the plunger.

Once I figured out this latest device, I've had NO failures, NO air bubbles, and NO problems testing with the Coag-Sense meter.

Of course, there can be a learning curve. In some cases, perhaps, self-testers need a bit of instruction on getting the drop into the transfer device and transferring it to the strip without getting air into the sample. And, perhaps, not enough blood was drawn into the tube initially - too little blood transferred to the strip might also generate an error.

Possibly, too, you got a bad set of transfer tubes.

Using the latest transfer tubes, after a bit of practice, I've had great success in running tests.

I realize that CoaguChek XS may be somewhat easier - especially touching the blood drop to the top or side of the strip. In my testing, I found that the Coag-Sense was both more accurate, and also usually reported a result slightly below that of the labs.

As far as the comment that a meter reporting an INR of .5 different from the lab results is accurate enough -- this is usually the case. But - it could mean that if your meter reports 2.1, the lab result may be 1.7 -- accurate, but dangerous if you have most valves.

A few years ago, I trusted my InRatio to be accurate. It repeatedly reported an INR of 2.6. I had a TIA (some doctors referred to this as a stroke). In the hospital, the INR that InRatio said was 2.6 was actually 1.7.

Personally, I prefer a meter that is equal to, or lower than, the lab result (the Coag-Sense usually is) - which means that if the Coag-Sys says 2.3, the lab result is probably between 2.3 and 2.6, than one that reports equal to or higher than the lab (as CoaguChek did in my testing). In this case, a 2.3 could mean that the INR is usually between 1.8 and 2.3.

Based on my testing, and ongoing experience, I personally prefer the Coag-Sense. With practice, it's easy to use. Plus, in my experience, it's more accurate. (And, no, I have no financial relationship to Coagusense Corporation).

I'm glad to see that some organizations are giving Coag-Sense meters to self-testers.

 

[Jamey T]

I agree with the slight learning curve of the Coag-Sense meter. At first I messed up a couple of test strips but I have only had one bad test in the last year, and for me, the accuracy is the same as Protimenow has said. I could never really trust mt Coagucheck, but I truly believe it is something with my blood chemistry that didn't agree with the way that the Coaguckeck does its testing.

 

[Protimenow]

The CoaguChek uses a measure of impedance, which changes while the blood is clotting. It's an electronic measure, and certain blood factors can affect the accuracy of the reading. For most people, it's accurate enough. For me, in my testing, I found that at times it was much higher than my lab results. Many of the times when the result was considerably higher than the lab, InRatio also reported high values. InRatio also used an electronic detection method and was eventually recalled and pulled from the market.

The Coag-Sense uses a mechanical method - it actually mixes the blood with a reagent, and a wheel moves the blood. When a clot forms, the wheel stops, and an optical sensor senses when the clot has formed. This mechanical method is similar to a method used in labs (tilt table) to detect physical formation of a clot.

Personally, I trust the Coag-Sense much more than I trusted the CoagChek XS. (I haven't used my CoaguChek XS for a few years and don't plan to get strips for it. My strips expired years ago. If I ever choose to do a new round of testing, I'll probably get a dozen or so, but I don't expect the results, compared to lab results and the Coag-Sense, to be much different than they were when I tested a few years ago).

 

[TomD]

I use Coag-Sense and about once a year I go in and do the test in my doctors office and then they do the test on their machine and we compare results. They have always been within 5%

 

[Protimenow]

TomD - I'm assuming that your doctor's office is using CoaguChek XS. Most are. I'm not surprised that the comparison between meters is within 5%. I wouldn't be surprised if the CoaguChek XS reported higher INR than your Coag-Sense.

I wouldn't be surprised if, over time, some busy doctor's offices may move to Coag-Sense because of its features that seem to have been designed for clinics and medical professionals. Of course, Roche probably has a much stronger marketing presence, but it would be good to see this become more of a two vendor business.

 

[Chris]

Thanks for the report on these. I'm eight days post-op and shopping for a meter. My medical group (current) doesn't allow self-monitoring, but I want to do if for my own information. I think I'm going to order one of these (Coag-Sense pt2).