I just got my new Coag-Sense meter...

[Guest]

And I tested it against my CoaguChek. The Coaguchek gave me an INR of 3.1 and the Coag-Sense gave me a reading of 2.5. After the comparison test I went back through my lab comparisons, and the 2.5 is right in line with previous lab tests when the CoaguChek had me in that range.

I won't have a chance to verify with a lab test for four more days, but after a total of one comparison test, I am happy with the new Coag-Sense meter. Time will tell if that holds out for me.

OK, now off to read the whole manual, not just watch the videos.

 

[Jamey T]

I guess I should have logged in first. Darn it.
For the record, this is my third meter, all of them different, so I do understand self testing, and I also have every INR test result I have ever had so I can track things.

 

[pellicle]

And I tested it against my CoaguChek. The Coaguchek gave me an INR of 3.1 and the Coag-Sense gave me a reading of 2.5. After the comparison test I went back through my lab comparisons, and the 2.5 is right in line with previous lab tests when the CoaguChek had me in that range.

I won't have a chance to verify with a lab test for four more days, but after a total of one comparison test, I am happy with the new Coag-Sense meter. Time will tell if that holds out for me.

Jamey

if you are going to compare results the blood samples must be taken within hours or at least the same day as INR can drift during the course of 24 hours, as you won't know which way it drifted you won't be able to rely on the comparisons. To remove these factors I always test with (in my case Coaguchek) device as soon as I get home from my blood draw. The INR the lab gets will be from that point in time.

Its good to hear you are documenting every test

 

[RobThatsMe]

I take my meter with me to the lab whenever I want to do a comparison test. I have been doing this since 2001 and have never had any issues with the lab allowing me to test right after they have taken their draw. So samples are taken within minutes. you should also ask the lab what reagent they are using in the lab in their blood analysis, and compare to see if it is the reagent your meter uses.

Rob

 

[Jamey T]

Jamey

if you are going to compare results the blood samples must be taken within hours or at least the same day as INR can drift during the course of 24 hours, as you won't know which way it drifted you won't be able to rely on the comparisons. To remove these factors I always test with (in my case Coaguchek) device as soon as I get home from my blood draw. The INR the lab gets will be from that point in time.

Its good to hear you are documenting every test

Pellicle,

Yes, I am aware of that. It is good that you said something for people just considering it though, I should have mentioned it in my post. Thank you.

My tests are usually within 15-20 minutes of each other. Yeah, I live that close to the clinic but it isn't a coumadin clinic, and they test in house, they don't send it out. I just had to do a test, since it was a new toy! I will do several side by side tests so I get a comfort level with the new meter.

 

[pellicle]

Rob raises a good point ...

... you should also ask the lab what reagent they are using in the lab in their blood analysis, and compare to see if it is the reagent your meter uses.

so with the rabbit hole in sight I'll mention that the Coagucheck uses a different methodology (not the falling ball for instance) to determine Prothrombin TIme. Machines like the iStat use similar methods. If they do take your INR and are processing it "in house" then they're more than likely using an iStat (or maybe even a Coaguchek?). This chart (and text) is helpful to grasp what a difference the chemistry method used to determine PT (and thence INR) in this study.

[IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/c2.staticflickr.com\/6\/5784\/21878002284_075c4a55ce_b.jpg"}[/IMG2]

and yes, Jamey T , I normally put this extra stuff here in the main for the "lurkers" who may read it (even via Google)

 

[tom in MO]

The table shows a spread of 20-25% of the INR value (100xdiff/median) based on measurement technique. This doesn't look too bad, particularly if your therapeutic range is 2-3.

However given the target range of 2-3 is only 1 INR and given a analysis technique range of INR results (i..e. "Diff") of 0.4 to 0.8, this is 40 to 80% of most people's therapeutic range. You can be in range with one method and out by another. Doesn't look to "accurate" now.

This shows why there is no need to get too excited if you are out of range. It's also shows that comparisons between your home machine and a lab draw at a single point in time may not be very useful. If you've done successful comparisons for years, you have "validated" your meter (to some extent) and may not need to do it anymore or less frequently.

INR measurements are not "an exact science" by any means. Luckily for us, it doesn't have to be. Unfortunately some people may apply a level of concern to their INR that is not really supported by the analysis technique.

The question I have no answer for and have yet to find is: "When do you know your meter needs to be replaced?" Can't find that in the manual anywhere, even though they give you the meter for free to get you to buy the strips Hey that could mean they won't tell you when to replace the meter since the "free" meter is actually not too cheap.

 

[CazicT]

Weird that Thrombotest is the absolute bottom of the range for the 1st and 3rd measurement, but it is towards the top for the second one.

Looks like Neoplastin plus gives the most consistent down the middle readings and Innovin is consistently high.

Generally Coaguchek seems "lowish".

Is there anything to really glean from this? Should you take into consideration that coaguchek is lowish when deciding if you are in range or not?

When doctors give you a range, say 2-3, that is presumably based on something... Statistics from somewhere? If so what is the "standard" method of testing that generated those statistics?

I'm guessing there wasn't a standard method of testing and the statistics where generated using all of the various methods and all INR tests were considered equal, but I really don't know.

 

[pellicle]

...
I'm guessing there wasn't a standard method of testing and the statistics where generated using all of the various methods and all INR tests were considered equal, but I really don't know.

Cazic, your question is a good one and there are two answers

1) is the short answer which is a summary position based on giving you the best outcome "aim to stay in the middle of your range"

2) the rabbit hole of research (which if you don't have a science background will probably leave you wondering why you didn't stick with #1

I'll sumarise it as:

• using the first to hand WHO standard reagent the Prothrombin Time of a statistically relevant sample of the population was determined (you'll be well to grasp the Standard Deviation of that as well as the fact there is an average)
• this was used then in conjunction as a ratio of the PT of an Anti-Coagulation medicated person (on warfarin) and used as a ratio of AC divided by Normal to give the INR

Significant questions are:

• what was your PT before AC? (did anyone bother to determine it?) and
• what reagent was it done with? and
• how did that vary from a standard blood sample PT

Some readings to start you off:
http://www.practical-haemostasis.com/Miscellaneous/Miscellaneous Tests/isi_and_inr.html

https://en.wikipedia.org/wiki/Prothrombin_time#International_normalized_ratio

So when you emerge from following all the references in those and "pop back off the stack" (to use a computational term of nested interrupts) to here again I reckon that you'll see the wisdom of sticking with answer #1)

We know there is a range, we know that you come to harm only on the extreems of that range, we have recently had a post from a patient who was using the "low INR protocol" (*as advertised by On-X) and came to harm.

My Grandfather was a good tennis player ... he always said "Get back to the middle of the court"

Thus over the last 6 years my INR mean has been 2.5 and my Standard Deviation = 0.4 (across that same period as well as dissected into yearly) resulting in that 98% of the time I'm within the range.

If my 2.5 is really (by some other method 2.3 or 2.6... well so what?

 

[tom in MO]

...We know there is a range, we know that you come to harm only on the extreems of that range, we have recently had a post from a patient who was using the "low INR protocol" (*as advertised by On-X) and came to harm...

Can you post a link?
Thx,
Tom

 

[pellicle]

Can you post a link?

http://www.valvereplacement.org/for...e-of-onx-valve-and-problems-with-lowering-inr

 

[RobThatsMe]

Hi,

I guess the concern that I see in this study is two fold, the study called for aspirin and Plavix. Patient could not take aspirin. So why stay on the study using Plavix alone. This brings me to my next concern. All the commercials I see for Plavix and other drugs like it clearly say "not for people with mechanical heart valves". I have always been told only Warfarin / Coumadin is to be used for anticoagulation in people with mechanical heart valves.

I do know of a friend that has an On-x Valve, aortic position, is on Coumadin and is maintaining a 1.5 - 2.0 INR range. He has been doing this for almost 3 years and so far, all his followups with his doctor are all very good.


...From original poster of the link pellicle provided above...
"There was a possibility at the time of the surgery… Or 90 days after, of being admitted into Onx study that utilized Plavix and aspirin for anticoagulation. It was found that my body did not properly react to aspirin so I was removed from the study by on X. On x had it documented in their database that my body does not react to aspirin."

Perhaps I am not aware of some of the newer test results for some of these new anticoagulants. I have not seen any that have mentioned safe for use with patients having mechanical heart valves. Would like to read the links if there are some out there.

Thanks,,
Rob

 

[pellicle]

Hey Rob

I do know of a friend that has an On-x Valve, aortic position, is on Coumadin and is maintaining a 1.5 - 2.0 INR range. He has been doing this for almost 3 years and so far, all his followups with his doctor are all very good.

well I'd expect that they would indeed be doing well ... as long of course as one can maintain that range and not dip out too far low. That's my only reservation with the low coagulation regime. In light of the above "ranges" and "what's your INR really" it seems prudent in the light of evidence and "risk analysis" to shoot for a 2.5 target knowing that "you might be 3 or you might be 2 when reading 2.5" and know that it doesn't matter.

It is of course up to the individual to make their own decision, I'm just expressing my views. People can just throw the bottle out the window and not take them a all (of which we have some evidence isn't as horrible a death sentence as some would suggest)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4818019/ [h=1]Longest Event-Free Survival without Anticoagulation in a Mechanical Aortic Valve Replacement[/h] I know where I sit on the risk analysis decisions ...

 

[dick0236]

I know where I sit on the risk analysis decisions ...

Me too. I try to stay around 3.0........and have had no issues since the beginnings of the INR system(no clots, no bleeds, no problems). My only problem came in the 1970s........when anti-coagulation management(pro-time) was done by "seat of the pants" experience of docs and long before the introduction of the INR system......and home testing.

BTW, my cardio jokingly wonders if my long term use of warfarin might partly explain my youngish appearaance, no gray hairs, little hair loss and a pretty sharp mind for an 82 year old......who knows......after all, many people us botox and other toxins to ward off aging......maybe wafrarin is really a very good "fountain of youth" drug.......ya think?

 

[pellicle]

...
BTW, my cardio jokingly wonders if my long term use of warfarin might partly explain my youngish appearaance, no gray hairs, little hair loss and a pretty sharp mind for an 82 year old......who knows......after all, many people us botox and other toxins to ward off aging......maybe wafrarin is really a very good "fountain of youth" drug.......ya think?

you could well be onto something, I think it may have played a part in saving Julien Du's leg. Although my friend observed that I've greyed a bit in the last 3 years, perhaps I should have started earlier.
Either way, I think I'll stay on it for life.

 

[Agian]

No grey hair at 82!? For real?

 

[Agian]

PS I was getting my hair cut and watching my dry, greying locks fall on the sheet. In despair, I exclaimed 'that looks like dog hair', the girl without missing a beat replies 'yep'. I was expecting some empathy.

 

[dick0236]

No grey hair at 82!? For real?

Uh.......maybe I have one or two grey hairs, but I attribute those to raising two sons. I get a little pissed 'cause I still have to go to a barber once a month and get by longer winter bur or my summer short bur.......and have to pay $10 (for a quick 10 minute mower cut) when all my bald friends can spend their $10 in a more productive way.....like betting on closest to the pin while playing golf.

 

[pellicle]

Dick

....and have to pay $10 (for a quick 10 minute mower cut) when all my bald friends can spend their $10 in a more productive way.....like betting on closest to the pin while playing golf.

I cut my own with clippers, set it to #2 and don't need to do it again for a while

 

[pellicle]

Hi

PS I was getting my hair cut and watching my dry, greying locks fall on the sheet. In despair, I exclaimed 'that looks like dog hair', the girl without missing a beat replies 'yep'. I was expecting some empathy.

Was it your daughter?