Ross
Well-known member
Look at the PT seconds and INR's. I'm assuming they are all using an ISI of 2 in the lab. I'm still trying to figure out how they came up with 3.8 and 23.6 seconds.
Al, does something look funny here?
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P
perrybucsdad
That does look funny Ross. You would think that with the same lab the ISI would be the same, and there would be a relationship between the INR and the PT seconds on following tests, but it seems to be all over the place.
Ross
Well-known member
My point exactly, that's why I don't go there for testing anymore and home test instead. They were changing my dose all around all the time and I was getting vein sticks every two weeks back then.perrybucsdad said:
P
Patrick
That is mad!
That is mad!
Greetings from Ireland!
That is indeed a very strange set of data. You should be able to work out the ISI by working backwards. INR=(PT/MNPT)to the power of the ISI, therefore if (PT/MNPT)=N, the ISI=LogINR to the base N. This is presuming a good average of the MNPT is 12.5.
Having said this there could be a serious difference in ISI values and possibly there may be a typo error involved?
I also home test and medicate with the CoaguChek-S but I have found consistent differences in hospital v home results. In fact I have a conversion graph to read my home result and the estimated hospital result. This has worked well for the last year or so.
Have you any comments on this? Unfortunately I am off line soon but will pick this up tomorrow.
Take care,
Patrick
That is mad!
Greetings from Ireland!
That is indeed a very strange set of data. You should be able to work out the ISI by working backwards. INR=(PT/MNPT)to the power of the ISI, therefore if (PT/MNPT)=N, the ISI=LogINR to the base N. This is presuming a good average of the MNPT is 12.5.
Having said this there could be a serious difference in ISI values and possibly there may be a typo error involved?
I also home test and medicate with the CoaguChek-S but I have found consistent differences in hospital v home results. In fact I have a conversion graph to read my home result and the estimated hospital result. This has worked well for the last year or so.
Have you any comments on this? Unfortunately I am off line soon but will pick this up tomorrow.
Take care,
Patrick
Ross
Well-known member
Patrick could you possibly email a copy of that graph or chart you have?
P
perrybucsdad
I'd like to see that graph too. Removed by Ross for safety
G
Guest
We use an ISI of 2.0 (CoaguChek-s) and for an INR of 3.7 the PT is 23.4 seconds.
I do not EVER report the PT to doctors. It just confuses the issue. In almost 8 years it has worked for me. The INR was developed because doctors were remembering a PT range that they wanted their patients to be in and never considered that it changed every time they got new batches. When the INR system began to be used they went back and looked at the old results and reconstructed what had happened. They found that some doctors were keeping patients at PTs that equalled INRs of around 8.0. No wonder people bled and that people facing warfarin therapy today are worried sick about it.
The ISI will vary from company to company and even from batch to batch of the same material. St. Agnes Hospital in Philadelphia killed several people about 5 years ago because someone failed to key in the correct ISI.
If you want to use a chart comparing yoiur home meter to the hospital's results remember that hospital reagents are often calibrated to ISI of 1.1, 1.2 etc and change constantly - so you are always comparing apples to oranges if you are trying to make one PT equal another.
Personally I think knowing the PT is about as useful as if the the sportscaster said, "Yankees 2". You have no idea of whether it is good or bad.
I do not EVER report the PT to doctors. It just confuses the issue. In almost 8 years it has worked for me. The INR was developed because doctors were remembering a PT range that they wanted their patients to be in and never considered that it changed every time they got new batches. When the INR system began to be used they went back and looked at the old results and reconstructed what had happened. They found that some doctors were keeping patients at PTs that equalled INRs of around 8.0. No wonder people bled and that people facing warfarin therapy today are worried sick about it.
The ISI will vary from company to company and even from batch to batch of the same material. St. Agnes Hospital in Philadelphia killed several people about 5 years ago because someone failed to key in the correct ISI.
If you want to use a chart comparing yoiur home meter to the hospital's results remember that hospital reagents are often calibrated to ISI of 1.1, 1.2 etc and change constantly - so you are always comparing apples to oranges if you are trying to make one PT equal another.
Personally I think knowing the PT is about as useful as if the the sportscaster said, "Yankees 2". You have no idea of whether it is good or bad.
Ross
Well-known member
I just wondered because one chart I do have is marked off in different ISI, but nothing corelates, so maybe I'm just confusing myself?
G
Guest
Just stick with the INR.
The INR makes all of the calculations and allows you to compare tests between the same meter, tests between different meters, tests between hospitals, and even different countries.
The only place that the INR system does not work well is when you have a high ISI and the PT is way above the range. Because it is an exponent function, an INR of say 50 or 100 might not be very accurate. For INRs below 8, or so, it is very accurate. The inherent variability of the testing system is higher than the variation caused by various ISI levels, in most cases.
The INR makes all of the calculations and allows you to compare tests between the same meter, tests between different meters, tests between hospitals, and even different countries.
The only place that the INR system does not work well is when you have a high ISI and the PT is way above the range. Because it is an exponent function, an INR of say 50 or 100 might not be very accurate. For INRs below 8, or so, it is very accurate. The inherent variability of the testing system is higher than the variation caused by various ISI levels, in most cases.
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Patrick
Hi Ross,
I will send yourself and ?perrybucsdad? a copy of my chart in PowerPoint and JPEG format (I am Macintosh based, not Windows or Xp). This chart is specific for my use as it is produced from data I gathered on myself and I am not suggesting that it is a general chart for all users.
CoaguChek is new here in Ireland and I only know of two other people with meters. I am gathering their data at the moment with a view to producing the same type of chart for them. I only work with the INR for comparison purposes and fully accept ?allodwick? comments about PT?s.
I have produced my chart with data I gathered on myself using two different meters and three batches of strips that I compared with two different hospital testing systems. I have charted differences up to about 30% and as you will see the relationship is non linear.
Already with the limited data I have from one of the new meters I can see the trend is different to the one I have. Much of the published literature indicates that hospital INR readings tend to be higher than the monitor but this has not been my experience. However this is now appearing to be the case for one of my new friends. We will have to wait and see.
I think it may be similar to zeroing in a rifle-scope, perhaps it needs to be done for each combination of individual home user and hospital?
Patrick
I will send yourself and ?perrybucsdad? a copy of my chart in PowerPoint and JPEG format (I am Macintosh based, not Windows or Xp). This chart is specific for my use as it is produced from data I gathered on myself and I am not suggesting that it is a general chart for all users.
CoaguChek is new here in Ireland and I only know of two other people with meters. I am gathering their data at the moment with a view to producing the same type of chart for them. I only work with the INR for comparison purposes and fully accept ?allodwick? comments about PT?s.
I have produced my chart with data I gathered on myself using two different meters and three batches of strips that I compared with two different hospital testing systems. I have charted differences up to about 30% and as you will see the relationship is non linear.
Already with the limited data I have from one of the new meters I can see the trend is different to the one I have. Much of the published literature indicates that hospital INR readings tend to be higher than the monitor but this has not been my experience. However this is now appearing to be the case for one of my new friends. We will have to wait and see.
I think it may be similar to zeroing in a rifle-scope, perhaps it needs to be done for each combination of individual home user and hospital?
Patrick
Ross
Well-known member
I'd appreciate it Patrick. I don't plan on using it for anything, but you sparked my interest in seeing it. 
G
Guest
The other thing to consider is that the test is not always reproducable. We frequently test three or four meters by placing drops of blood from the same fingerstick on meters lined up side-by-side. You will get 2.1, 2.5, 1.9 and 3.0.
The with the next patient you will get 3.0, 3.0, 3.1 and 3.0.
It is the problem like the man with one watch. He always knows the time. If the man has more than one watch, he never knows what time it is. As I have observed numerous times, trying to systmetize INR testing drives engineers crazy.
The best thing to do is just accept my method. Don't let the INR go more than 0.2 units below your desired range without increasing the dose and don't go above 5.0 without reducing the dose. It makes it so much easier than always worrying.
The with the next patient you will get 3.0, 3.0, 3.1 and 3.0.
It is the problem like the man with one watch. He always knows the time. If the man has more than one watch, he never knows what time it is. As I have observed numerous times, trying to systmetize INR testing drives engineers crazy.
The best thing to do is just accept my method. Don't let the INR go more than 0.2 units below your desired range without increasing the dose and don't go above 5.0 without reducing the dose. It makes it so much easier than always worrying.
P
Patrick
Dear Al,
While I accept totally that tests are not always reproducible, it is well worth considering that they should be! If anyone was running four different meters with a chip in each then they may possibly be running up to four different test-strip batches also? There is published acceptability of a 20% variation in test results according to manufacturers of Coaguchek S. I find this variation high and have even recorded higher variations myself. Therefore I have tuned the results of my monitor to myself and believe I can reliably predict the hospital equivalent much more accurately. For me this shows that it is necessary to know your own machine! One man, one watch, but set to GMT.
I take 8mg each evening at 19:00, most occasions when my INR has gone high I could find a reason and eliminate or reduce the cause (usually diet, medication or flu etc.). So far I have rarely had to reduce my medication dose. When it has dropped too low and I needed intervention, I increased my dose by 1mg each night until it came back up, but this took several days. Now if I drop low I take 1mg at 09:00 and the usual 8mg at 19:00 this will get me back to my range within a day or two at most. I then go back to my normal 8mg daily. Consistency of medication and diet seems to be the name of the game?
Patrick
While I accept totally that tests are not always reproducible, it is well worth considering that they should be! If anyone was running four different meters with a chip in each then they may possibly be running up to four different test-strip batches also? There is published acceptability of a 20% variation in test results according to manufacturers of Coaguchek S. I find this variation high and have even recorded higher variations myself. Therefore I have tuned the results of my monitor to myself and believe I can reliably predict the hospital equivalent much more accurately. For me this shows that it is necessary to know your own machine! One man, one watch, but set to GMT.
I take 8mg each evening at 19:00, most occasions when my INR has gone high I could find a reason and eliminate or reduce the cause (usually diet, medication or flu etc.). So far I have rarely had to reduce my medication dose. When it has dropped too low and I needed intervention, I increased my dose by 1mg each night until it came back up, but this took several days. Now if I drop low I take 1mg at 09:00 and the usual 8mg at 19:00 this will get me back to my range within a day or two at most. I then go back to my normal 8mg daily. Consistency of medication and diet seems to be the name of the game?
Patrick
Marty
Well-known member
INRatio = isi 1.0
INRatio = isi 1.0
I talked to a techie at Hemosense about the results with my new INRatio which I like very much. I was assured the isi for its thromboplatin is always 1.0. I like this, as I was never too good with exponents. The PT's are much longer than those with my 7 year old Coaguchek Classic.
INRatio = isi 1.0
I talked to a techie at Hemosense about the results with my new INRatio which I like very much. I was assured the isi for its thromboplatin is always 1.0. I like this, as I was never too good with exponents. The PT's are much longer than those with my 7 year old Coaguchek Classic.
G
Guest
I have looked at the statistics for my clinic. Minor bleeding occurs at the rate of 1 per 1.5 patient-years. Major bleeding 1 per 33 patient-years. Clotting 1 per 100 patient-years.
These are very acceptable levels in the medical field.
The level of technology we have today is probably as good as it is likely to get in the forseeable future.
If the variability got down to 10% there would not necessarily be a halving of the rates of complications. But even if it did, would it be worth the effort. 1 minor bleed per 3 patient-years would probably not be perceived as any different by the average person. Likewise 1 major bleed per 66 patient-years or 1 clot for 200 patient-years.
So that is why I say just keep the INR between 0.2 units low and less than 5.0. For 30,000 vists patients and doctors have been happy with the results.
These are very acceptable levels in the medical field.
The level of technology we have today is probably as good as it is likely to get in the forseeable future.
If the variability got down to 10% there would not necessarily be a halving of the rates of complications. But even if it did, would it be worth the effort. 1 minor bleed per 3 patient-years would probably not be perceived as any different by the average person. Likewise 1 major bleed per 66 patient-years or 1 clot for 200 patient-years.
So that is why I say just keep the INR between 0.2 units low and less than 5.0. For 30,000 vists patients and doctors have been happy with the results.
P
Patrick
Very comforting results there Al!
Huge number of visits, how large was the cohort and how are minor and major bleeds differentiated or defined?
As to the current level of coag technology, I am always surprised at how some small innovations can improve standards exponentially on occasions.
The active inclusion of real (separate reading) internal controls on each testing strip would be significant in defining accuracy and user confidence. I can only presume that is in the pipeline for the next generation of coag monitors?
I can?t argue with your 0.2 / 5.0 limits from your results. Well done!
Patrick
Huge number of visits, how large was the cohort and how are minor and major bleeds differentiated or defined?
As to the current level of coag technology, I am always surprised at how some small innovations can improve standards exponentially on occasions.
The active inclusion of real (separate reading) internal controls on each testing strip would be significant in defining accuracy and user confidence. I can only presume that is in the pipeline for the next generation of coag monitors?
I can?t argue with your 0.2 / 5.0 limits from your results. Well done!
Patrick
G
Guest
The cohort was about 2,500 patient visits. I don't recall the actual number of people. It was everyone that I saw for that year. (I probably see at least twice that many now.)
The definition of a minor bleed was anything that required a person to stop what they were doing to attend to the bleed for the minimum. The upper definition was anything that did not require blood products. So a spot on a handkerchief was not a bleed. Blood on the pillow case was a minor bleed. Getting vitamin K was a minor bleed. Going to the ER to have a spot cauterized was minor.
Major bleeds were anything that required a transfusion.
All clots were considered major. I had a lot of people with clotting disorders who got a clot in their leg if they got down to an INR of 2.0 - so the number is probably higher than if they were just valve patients without the clotting disorder.
The definition of a minor bleed was anything that required a person to stop what they were doing to attend to the bleed for the minimum. The upper definition was anything that did not require blood products. So a spot on a handkerchief was not a bleed. Blood on the pillow case was a minor bleed. Getting vitamin K was a minor bleed. Going to the ER to have a spot cauterized was minor.
Major bleeds were anything that required a transfusion.
All clots were considered major. I had a lot of people with clotting disorders who got a clot in their leg if they got down to an INR of 2.0 - so the number is probably higher than if they were just valve patients without the clotting disorder.
C
cocoalab
A little question about dosing
A little question about dosing
Obviously this is just a curiosity thing as Andrew is no longer on Coumadin but I was wondering if there is an average dose that people require of Coumadin/ Warfarin? Andrew had taken Coumadin since 6ys and his dose really didn't go up that much for how much he grew in that time period.
He was taking only 2 to 3 mgs each night. Sometimes he would get the 3 mg 3x a week sometimes 4x a week occasionally 5x. I believe he started at 1 and a half mgs a night. His results were very stable (for the most part) the first several years.
his range was at first 2.5 to 3 and then they changed to 3 to 3.5 desired range. I always used the same hospital lab though I did change to another one the last few months.
Anyways we would go too high and change one of his doses down to the 2 mgs and then a week or two later he would be too low. sometimes dropping dramatically. Example 4.2 to 2.0 in one week. Looking at this it seems he did skip one dose as well that time. He also went from 2.2 INR to 4.5 in 2 weeks with only an increase of 1 mg a week.
I understad diet and other things influence the INR but we just never got stabilized lately he had previously been able to have monthly testing, and he was followed by the same nurse (INR Manager).
Andrew also showed sensativity to Heparin when changing over for different proceedures he would have to be stopped and restarted.
Anyone have any insight to these issues? I wish I had known about this group years ago.
Also Andrew was at 4.5 a week and a day before his surgery with a previous INR of 2.2, just shy of 2 weeks before and a change of 1 mg a week. We gave him 1 mg of Coumadin the next night and then stopped him 4 days before admitting him for heparin bridge. His INR on Tuesday was 1.2 one day after admittance with a ptt of 39 goal of 60 to 100 for heparin I believe. I do not know what his INR was on monday but I think that might have been the midnight draw's lab.%2%0
Anyways Andrew in 9 years never had a significant bleed or really much bruising; his younger non coumadin taking brother bruises much easier. He has had a few nose bleeds but within range of how long they should be.He had one incident in the ER that said he was at 7. something and had a little blood in the urine. His previous month was fine and it was a different lab but they did retest him to confirm it. he went back to normal range awful quickly though. ?
Does it seem that he is especially sensitive to coumadin as far as dosing is concerned ,or is it a hormonal/ growth thing that may have made him so hard to manage lately? His cardiologist really didn't have any answers to this. Sorry this is so long but thank you for any insite you all could give me.
heart hugs,
wendy
A little question about dosing
Obviously this is just a curiosity thing as Andrew is no longer on Coumadin but I was wondering if there is an average dose that people require of Coumadin/ Warfarin? Andrew had taken Coumadin since 6ys and his dose really didn't go up that much for how much he grew in that time period.
He was taking only 2 to 3 mgs each night. Sometimes he would get the 3 mg 3x a week sometimes 4x a week occasionally 5x. I believe he started at 1 and a half mgs a night. His results were very stable (for the most part) the first several years.
his range was at first 2.5 to 3 and then they changed to 3 to 3.5 desired range. I always used the same hospital lab though I did change to another one the last few months.
Anyways we would go too high and change one of his doses down to the 2 mgs and then a week or two later he would be too low. sometimes dropping dramatically. Example 4.2 to 2.0 in one week. Looking at this it seems he did skip one dose as well that time. He also went from 2.2 INR to 4.5 in 2 weeks with only an increase of 1 mg a week.
I understad diet and other things influence the INR but we just never got stabilized lately he had previously been able to have monthly testing, and he was followed by the same nurse (INR Manager).
Andrew also showed sensativity to Heparin when changing over for different proceedures he would have to be stopped and restarted.
Anyone have any insight to these issues? I wish I had known about this group years ago.
Also Andrew was at 4.5 a week and a day before his surgery with a previous INR of 2.2, just shy of 2 weeks before and a change of 1 mg a week. We gave him 1 mg of Coumadin the next night and then stopped him 4 days before admitting him for heparin bridge. His INR on Tuesday was 1.2 one day after admittance with a ptt of 39 goal of 60 to 100 for heparin I believe. I do not know what his INR was on monday but I think that might have been the midnight draw's lab.%2%0
Anyways Andrew in 9 years never had a significant bleed or really much bruising; his younger non coumadin taking brother bruises much easier. He has had a few nose bleeds but within range of how long they should be.He had one incident in the ER that said he was at 7. something and had a little blood in the urine. His previous month was fine and it was a different lab but they did retest him to confirm it. he went back to normal range awful quickly though. ?
Does it seem that he is especially sensitive to coumadin as far as dosing is concerned ,or is it a hormonal/ growth thing that may have made him so hard to manage lately? His cardiologist really didn't have any answers to this. Sorry this is so long but thank you for any insite you all could give me.
heart hugs,
wendy
G
Guest
It is hard to put averages on children because they seem to develop in spurts. Not just physical size but probably in liver enzymes etc.
Heparin does not affect the INR even though it protects from clots.
Heparin does not affect the INR even though it protects from clots.
