Minor milestone today, 3 months

Help Support ValveReplacement.org:

scott.eitman

VR.org Donator
Joined
Jun 7, 2010
Messages
456
Location
Beachwood (Cleveland), OH
I just don't understand why people are taking their INR reading to the Nth degree. Pick a testing method and stick to it. This is not rocket science. If so, our ranges would not be so inexact. I was given a 1.5 - 2.0 range because that is what On-X determined was OK. The staff would freak when I was 2.1 We just raised the range and all is good.
 

Protimenow

Well-known member
Joined
Aug 10, 2010
Messages
2,756
Location
California
Monthly or yearly dose is a lot less practical than weekly dose.
There are some of us who don't take the exact same dose daily - varying slightly a day or two each week, to establish a dose that works best for them. And, as you well know, our needs don't always stay constant week to week, month to month, or year to year.

If we all took the same daily dose, every day, then the weekly dose thing is of no value.

If it was possible to stay in range using the same dose every day and be in the center of the range, then weekly dose is of no value.

Alternating doses a few times a week makes accurate INR measurement inaccurate, because it changes in relationship to the doses you took a few days ago.

Personally, I take the same dose every day - and don't really look at it as a weekly dose.

When I last made a change in my dose, I dropped from 7.5 daily to 7.0 daily (requiring 1 1/2 4 mg and 1 1 mg pill).

I wonder if, for convenience, going with 6.5 or 7.25 (if it's even possible) mg/day would still keep me in range.

If warfarin users can determine a daily dose that is easy to create (in the case of my 7 mg dose, a 5 mg and a 2 mg would be easier, but I don't have 5 mg pills on hand), and still stay in range, then daily dosing would be the way to go. HOWEVER, if 7 puts a person slightly below range, and 7.5 puts them at the high end of the range, what options are there? (Yeah, a 7.25 could be made by breaking a 7.5 mg in half, adding a 2 mg, a 1 mg, and a .5 mg).

But I'm assuming that a fairly standard dosing, without jumping through hoops to get to an effective dose would keep a person in range - in which case total weekly dose would be irrelevant.
 

Dodger Fan

Well-known member
Joined
May 6, 2015
Messages
99
Location
Temecula, CA , USA
You believe your machine is 0.3 to 0.4 points high. Be aware of your assumptions:
  • Blood draw reading is more accurate than meter. This assumes the lab is handling your blood properly and doing the test correctly. Some labs use a meter :) For example, your INR value from the blood draw could be off due to some systematic mishandling of the sample. When meter's performance are tested professionally, they use multiple reference laboratories.
  • Your meter error is linear, i.e. the same at any reading. You might want to make sure this is the case, but to do so you'd have to go out of range, which is probably not a good thing.
  • The error in the reading is in the meter and test strips and not your body chemistry. If the error is because of some unknown and unusual biochemical thing with your body, this can change over time. People's body chemistry changes all the time. The human body is always changing, always finding a new equilibrium until something else changes, your body adjusts, etc.
Thanks. I'm good. I got the receipts. No assumptions here.
 

Dodger Fan

Well-known member
Joined
May 6, 2015
Messages
99
Location
Temecula, CA , USA
I'm not sure that I agree with your strategy of reporting what you think is a correct value for your test to the clinic -- they may continue to round it down to account for the difference in values that your meter typically reports, and may advise dosage changes that shouldn't be made.
If I'm in a situation where I think I'm too low, I'll go get a blood draw, or call the clinic and come clean, or redose myself. It's working for the moment. I'm happy. I'm almost always in range. I'd probably have a second TIA if I put as much thought into it as some of you guys do. Everyone needs a hobby I guess 😉
 

Dodger Fan

Well-known member
Joined
May 6, 2015
Messages
99
Location
Temecula, CA , USA
Monthly or yearly dose is a lot less practical than weekly dose.
There are some of us who don't take the exact same dose daily - varying slightly a day or two each week, to establish a dose that works best for them. And, as you well know, our needs don't always stay constant week to week, month to month, or year to year.

If we all took the same daily dose, every day, then the weekly dose thing is of no value.

If it was possible to stay in range using the same dose every day and be in the center of the range, then weekly dose is of no value.

Alternating doses a few times a week makes accurate INR measurement inaccurate, because it changes in relationship to the doses you took a few days ago.

Personally, I take the same dose every day - and don't really look at it as a weekly dose.

When I last made a change in my dose, I dropped from 7.5 daily to 7.0 daily (requiring 1 1/2 4 mg and 1 1 mg pill).

I wonder if, for convenience, going with 6.5 or 7.25 (if it's even possible) mg/day would still keep me in range.

If warfarin users can determine a daily dose that is easy to create (in the case of my 7 mg dose, a 5 mg and a 2 mg would be easier, but I don't have 5 mg pills on hand), and still stay in range, then daily dosing would be the way to go. HOWEVER, if 7 puts a person slightly below range, and 7.5 puts them at the high end of the range, what options are there? (Yeah, a 7.25 could be made by breaking a 7.5 mg in half, adding a 2 mg, a 1 mg, and a .5 mg).

But I'm assuming that a fairly standard dosing, without jumping through hoops to get to an effective dose would keep a person in range - in which case total weekly dose would be irrelevant.
I have 5mg and 2.5mg so all of my doses come from those pills. I'm currently at 10mg daily, but I have had slight dose variations. For example 10mg per day except 8.75mg on Tuesday and Thursday. I attribute this to the pill sizes I am prescribed not always easily dividing perfectly into a daily dose.

For the last couple of years 8.75mg was my high dose. This year I've lost 60lbs. I'm running a lot and I'm requiring a lot more warfarin to stay in range.
 

Protimenow

Well-known member
Joined
Aug 10, 2010
Messages
2,756
Location
California
Years ago, before I had a meter, and before I got tested regularly, I had a large cache of 7.5 and 5 mg coumadin (the brand name stuff). I used to take 7.5 on days with a T in their name, and 5 on the other days. I didn't have a TIA, and didn't bleed out - so, without testing, I was able to get through quite a while unmonitored.

I was lucky. I don't suggest that ANYONE should go without testing.

Currently, I have a supply of 4 mg, 7.5 mg, and 1 mg warfarin. I'm going to see if my primary can prescribe some 5 mg (which will make it easier to assemble a 7 mg daily dose - until I need to modify the dose). I don't make dosage changes often, and I keep my doses the same each day, as long as my INR remains in range.

Be aware that if you're alternating between 10 mg and 8.75, your INR taken one day will be different from the one taken another day, because your INR will fluctuate just as the dosing fluctuated.
 

leadville

Premium Level User
Joined
Aug 28, 2017
Messages
252
Location
Greater Manchester, England
I'm running a lot and I'm requiring a lot more warfarin to stay in range.
@Dodger Fan

Interstering ,

I cycle and run and when i do heavy or long cardio i need less warfarin

The cardio shows a considerable INR rise at the same warfarin Dose

In one week say 3 x 50-70 mile bike rides would up me ~ 0.6 -1.0 with all
other variables the same

3 x 10k runs ~ 0.6

Congratulations on the 60lb Drop (y)
 

scott.eitman

VR.org Donator
Joined
Jun 7, 2010
Messages
456
Location
Beachwood (Cleveland), OH
I just do not understand the need to test weekly. I am not a medical person, but the ranges are guidelines, not hard and fast rules. Being point one high, you will not bleed out and point one low will not cause clotting.

I eat a plant based diet. Meaning only plants. I test every 6 weeks at the Cleveland Clinic Anti-coagulation Clinic. I firmly believe testing too frequently will drive people crazy. Yes, if I am out of range, I will need to go back earlier, maybe in 2 weeks.
 

tom in MO

Well-known member
Joined
Jan 17, 2012
Messages
1,099
Location
MO USA
Tom - I'm not sure that I agree with your statement that the lab reading is more accurate than the meter. I've reported on recent tests that show this - even values for blood taken a short time apart, but taken at different places, gave different results.

We should take into account, too, that INR testing doesn't give an exact value - 20% variance between meter and lab is acceptable. In my experience, when labs 'get it right' their results are often slightly lower than the CoaguChek XS, and often slightly higher than the Coag-Sense. All of these are within 20% of the lab's findings.

The meter error in the XS is NOT linear - it's been reported that the error increases the higher the INR becomes. A .3 error in an INR of 2.5 may turn into a .5 (or higher) error for an INR above 4. (High INRs should be rechecked).

Body chemistry DOES affect the results of a CoaguChek XS -- certain disorders will render the meter's result inaccurate.

The Coag-Sense uses a different method of determining INR - it actually records the time that it takes for a clot to form, then divides the time by a value for the reagent.

I suspect that DodgerFan's INR as measured on the CoaguChek XS probably IS higher than the lab results. Although it's higher than the lab, it's still within the 20% range of error. I'd only worry if it gives me an INR below 2.2 or so.

I spoke to my primary (his lab gave me a 3.88) and told him that I thought the lab was wrong, because the results on my meters nearly matched each other, and the tests that I've taken every week for a month or two. (My results on my meters ranged from 2.7 to 3.0 over a period of more than one month, and were 2.7 and 3.0 a few days after my blood was drawn, when I got the lab results).

I asked, and he offered, to have the phlebotomist draw two tubes of blood the next time I was in his office, and to send it to two different labs. This approach may show how much agreement there is in the results of the two labs (on THAT day, at least). I'll also, of course, do a test on one or both of my Coag-Sense meters, and we can compare all results. (If I had a supply of CoaguChek XS strips, I'd also run a test on my XS -- but I don't have the strips and can't afford any at this time).

For me, trusting the labs is getting more and more difficult.
Sorry for some confusion, I don't assume that the lab reading is more accurate, I was pointing out the assumptions behind DodgerFan's self-correction of his INR. Built into his belief are the three assumptions, if any one of the assumptions is incorrect then he might not want to apply the correction.
 

tom in MO

Well-known member
Joined
Jan 17, 2012
Messages
1,099
Location
MO USA
I have 5mg and 2.5mg so all of my doses come from those pills. I'm currently at 10mg daily, but I have had slight dose variations. For example 10mg per day except 8.75mg on Tuesday and Thursday. I attribute this to the pill sizes I am prescribed not always easily dividing perfectly into a daily dose.

For the last couple of years 8.75mg was my high dose. This year I've lost 60lbs. I'm running a lot and I'm requiring a lot more warfarin to stay in range.
Congratulations on the 60lb drop. Wish I could do it, what was your strategy?
 

Protimenow

Well-known member
Joined
Aug 10, 2010
Messages
2,756
Location
California
Scott:

I base my push for weekly monitoring on a paper by Duke University Clinics that said that a person can have a TIA after only one week with an INR below 2. That's ONE WEEK.

I had a TIA a few years ago, because I put too much trust in the accuracy of my InRatio meter...it gave me an INR of 2.6 - at the hospital, it was 1.7.

Your assumption that your INR would only deviate .1 or .2 up or down from your usual level sounds good - and most of the time is correct. From personal experience, though, I've seen my INR drop, without reason, below 2 a few times. I quickly adjusted my dose, and in one case where it dropped close to 1, I used Lovenox injections to prevent an issue until my INR came back up.

If I only tested monthly (or, egads, every 12 weeks), I wouldn't have detected the strange drop in INR and could have been in real time, if I allowed my INR to stay that low.

I've been self-testing for more than 10 years. I've used a variety of meters. I've not always tested every week, but I'm aware of the risk if I don't test weekly.

Testing weekly is not a big deal. I don't see weekly self-testing 'driving people crazy.' It's not that big a deal. Diabetics test much more frequently, and they don't seem to have gone crazy because of frequent testing.

If you're comfortable with testing less frequently, go ahead. Some clinics and practices stretch the time between tests out for patients whose INRs are stable. For me, though, a weekly test is no big deal, and I feel more comfortable knowing that my INR is in range than I would if I was concerned tat it wasn't.

(Also, I'm sure others will probably confirm this, weekly self-testing is the standard of care in some countries -- and is recommended by the meter manufacturers who, obviously, make money from the sale of strips but probably also have some concern about patient outcomes).
 

pellicle

Professional Dingbat
Joined
Nov 4, 2012
Messages
6,457
Location
Queensland, OzTrayLeeYa
...There are some of us who don't take the exact same dose daily - varying slightly a day or two...
you have yet to outline what any possible benefit to knowing your weekly dose is? So far everything you've written confirms that knowing your daily dose and perhaps (for reasons of convenience not mentioned) adjusting that to a few mg over and under the daily dose in an alternating way.
 

pellicle

Professional Dingbat
Joined
Nov 4, 2012
Messages
6,457
Location
Queensland, OzTrayLeeYa
I just do not understand the need to test weekly.
the benefits of testing weekly are that you will pick up out of range situations faster and thus be in range more of the time. All the studies agree that time in theraputic range is the largest factor for avoiding any harm (bleed or stroke) from being on AntiCoagulation Therapy.

Indeed On-X required the weekly testing protocol for their proact study to get their INR range lowered to 1.7, so valve makers they see the benefits of weekly testing.
 
Top