New Coag-Sense meter

[tom in MO]

You are asking for a level of agreement (i.e. 0.1) that is not possible with the INR test either in-lab or at home. It's also not needed for the decision as to whether or not your dose is correct.

I know you are asking Pellicle for a response, however some parts of your post are confusing, for example:

• "I am trying to compose a letter to my insurance company to ask them to let me know what reagent they use in their lab." Insurance companies generally do not have labs.
• Right now, the company purchases the reagents independently of the lab and does not inform either the lab or the anti-coagulation pharmacists of changes in advance. Reagents in laboratories and for office or home monitoring devices have to change. They are depleted as used or if not used they expire.
• The purchasing agents probably have no idea that it might be hazardous for the patients or handicap the doctors and pharmacists and simply do not know enough to ask. Purchasing agents buy what they are told based upon a laboratory's technical personnel's purchase order.

 

[Protimenow]

Your concern is way off base. INRs are not exact - they're within a range of accuracy. You can test blood, using the same meter, a few minutes apart, and come up with different results. A lab can test the same blood different times, using the same reagents, and come up with results that don't match.

The target for INR testing is WITHIN a certain point - a range of values. It isn't, and can't be, exact.

Further, each batch of strips - from Roche or Coagusense - has its own reagent values. That's why Roche supplies a code chip with each tube of strips, and why Coag-Sense puts a printed code on its strips and the new packages of Coag-Sense strips also have a code that is scanned by the meter.

Further, the idea of 'calibrating' your meter is nonsense. These meters aren't designed to be externally 'calibrated.' The 'calibration' exists on the code chip for Roche and the code that is printed on the Coag-Sense strip. Years ago, Hemochron and other early meters COULD be calibrated, but at this point, it's ancient technology.

Roche and Coagusense stake their Meter business on the continued, constant accuracy of the meters and strips. The meters have also gone through FDA testing for accuracy. Personally, with the awful results that I've gotten from labs recently, I prefer to trust the meters more than I do the labs.

So - take a deep breath - and another - and be comforted in the idea that a) INR results aren't precise, b) results appear within a range - usually within 20% of 'accurate', and c) your meter doesn't need anything done to it to improve its accuracy.

(BTW - if you have a Coag-Sense, I have extra strips that I would like to sell)

 

[Protimenow]

You are asking for a level of agreement (i.e. 0.1) that is not possible with the INR test either in-lab or at home. It's also not needed for the decision as to whether or not your dose is correct.

I know you are asking Pellicle for a response, however some parts of your post are confusing, for example:

• "I am trying to compose a letter to my insurance company to ask them to let me know what reagent they use in their lab." Insurance companies generally do not have labs.
• Right now, the company purchases the reagents independently of the lab and does not inform either the lab or the anti-coagulation pharmacists of changes in advance. Reagents in laboratories and for office or home monitoring devices have to change. They are depleted as used or if not used they expire.
• NO - the reagents used come in containers with the reagent values clearly printed on the container that they came in -- the labs - or clinics that perform the INR testing - clearly DO have the reagent values - they MUST have those values to run a test. If you use a meter, the strips either come with a chip that has reagent values or have a value printed to a label that is put onto the strip.
• The purchasing agents probably have no idea that it might be hazardous for the patients or handicap the doctors and pharmacists and simply do not know enough to ask. Purchasing agents buy what they are told based upon a laboratory's technical personnel's purchase order.
• Not entirely - the purchasing agents at a lab MUST know about the tests and the types of materials that they must purchase - if not, people may get hurt, the lab may get sued and, no matter what, either the purchashing agent would have to learn very quickly - or would be looking for a job on day two.

 

[ScribeWithALancet]

You are asking for a level of agreement (i.e. 0.1) that is not possible with the INR test either in-lab or at home. It's also not needed for the decision as to whether or not your dose is correct.

-- According to research by university medical schools with anti-coagulation clinics, it is possible to correlate Coag-Sense and CoaguChek meters with Lab Blood draws within 0.1 for most of the normal range of people taking blood thinners. This correlation uses standard regression techniques. This is needed for ME to convince my health insurance company (HMO) that the meter is accurate. They previously ran an internal test that showed that their lab blood draw tests were much more repeatable and accurate then the INR meters in use at the time. Since they were and are paying for both the meters and the lab tests and not charging the members for either, they have no financial benefit from the study results.

I know you are asking Pellicle for a response, however some parts of your post are confusing, for example:

• "I am trying to compose a letter to my insurance company to ask them to let me know what reagent they use in their lab." Insurance companies generally do not have labs.
• - - My insurance company is a HMO. It has both labs and coumadin specializing pharmacists. My HMO does not charge me for either the blood draws nor the INR tests using the blood draws nor the consultations with their Anti-Coagulation pharmacists.
• Right now, the company purchases the reagents independently of the lab and does not inform either the lab or the anti-coagulation pharmacists of changes in advance. Reagents in laboratories and for office or home monitoring devices have to change. They are depleted as used or if not used they expire.
• -- I agree with your statement. However, If they can change the type of reagent used in the machine that processes the INR for the lab, it can change the resultant INR while the patient has the same actual INR according to research that I have seen. At present the purchasing staff inform neither the Anti-Coagulation folks nor the Laboratory staff.
• The purchasing agents probably have no idea that it might be hazardous for the patients or handicap the doctors and pharmacists and simply do not know enough to ask. Purchasing agents buy what they are told based upon a laboratory's technical personnel's purchase order.
• -- Big bureaucracies do indeed buy what they are told. If machines can take more then one reagent, then they might buy the cheapest rather then the one that most closely matches the previous reagent? At present, there is no communication of information. While communication of the information might not save anyones life, it might allow more rational discussion when your INR changes for no apparent reason. Data might not help but it probably would not hurt. Would a change of the reagent to a different production run of the same reagent cause a change? Based on what Protime said about the calibration runs of the Coag-Sense and what Coag-Sense told me about their company using the same reagent for the last ten years, probably so. How much of a change, I cannot even guess at. I am glad that Coag-Sense is handling that end of the issue.

-- Everyone's health insurance company is a bit different and HMO's in particular march to different drummers. I am just trying to make my health insurance company like letting me march to my own drummer (a Coag-Sense) when I am on travel or on a multiple week absence from the blood draw lab.

Walk in His Peace,
David,
ScribeWithALancet

 

[ScribeWithALancet]

Reply to Protimenow, post: 893787, member: 7720
Your concern is way off base. INRs are not exact - they're within a range of accuracy. You can test blood, using the same meter, a few minutes apart, and come up with different results. A lab can test the same blood different times, using the same reagents, and come up with results that don't match.

-- I agree with this but my concern is convincing my health insurance plan. The studies that were done found you could find a close correlation between the lab and the Coag-Sense or CoaguChek using regression analysis. I will have to build my own data table and develop my own regression analysis. Who knows in advance what numbers will develop. However, they hopefully will be adequate to be convincing. No one is claiming they will be within 0.1 of reality. Pellicle's table is very convincing on that. Taking your blood several minutes apart and coming up with different results is an issue of repeatability. After I have learned to take my INR reliably and rapidly the first time, I will attempt to establish the level of repeatability of the meter. I need to know how close to the low and high ranges that I can get (with my meter and skill level) before I have to worry about being too close.

The target for INR testing is WITHIN a certain point - a range of values. It isn't, and can't be, exact.

-- Again, I am not using this to develop a target for my INR. That is 2.5 to 3.5 or hopefully 2.9 to 3.1 for my St. Jude Valve. Mostly, I do not want clots or bleeding. I have been on Coumadin/Warfarin for 15 years now and dislike both. Since I used to be pre-diabetic before I went on a near ketogenic diet (<24 grams of carbs and 90+ grams of fat per day). I measure everything I eat and now eat 300 mg of K1 +- 12.5 mg of K1 per day (estimated using Dept of Agriculture Nutritional Database and a chemists scale). This also gives me a very BAD estimate of K2 which varies all over the map. This is because of the Dept of Agriculture definition of Organic Grass fed agricultural products. >100 days per year of outdoor grass feeding. Meaning that "grass fed" meat, dairy and eggs can have a lot or little vitamin K2 in it. Organic Corn fed March dairy and meat might have very little K2. Animal gut bacteria usually make the K2 out of the K1 found in grass but not in corn or wheat.

Further, each batch of strips - from Roche or Coagusense has its own reagent values. That's why Roche supplies a code chip with each tube of strips, and why Coag-Sense puts a printed code on its strips and the new packages of Coag-Sense strips also have a code that is scanned by the meter.
-- While each batch of reagent strips from Coag-Sense has its own new printed code, Coag-Sense told me that they have not changed the chemical reagent they use in the ten years +- that they have been in production. It is just that when they get a new batch of the same reagent in, it is slightly different. However, it is probably closer then the different reagents that are in Pellicle's table from Roche/CoaguChek.

This is pure speculation on my part as I have not yet gone thru my first 50 strips in my first month although I appear to be trying hard as I attempt to speed up my efficiency in transferring the blood from my finger to the test strip.

I had heard a rumor that CoaguChek changed the reagent or reagent manufacturer on their recalled strips but have been unable to find any information on line about this. It could just be that their reagent manufacturer messed up.

Further, the idea of 'calibrating' your meter is nonsense. These meters aren't designed to be externally 'calibrated.' The 'calibration' exists on the code chip for Roche and the code that is printed on the Coag-Sense strip. Years ago, Hemochron and other early meters COULD be calibrated, but at this point, it's ancient technology.

-- The calibration that I am trying to achieve is a regression analysis where I can use the regression equation to predict the INR that my blood draw lab would produce from their machines and reagent. I am not talking about any kind of real world calibration. Perhaps correlation would be a better word. My goal is to statistically demonstrate that
(1) my Coag-Sense produces a good estimate of my INR. (I have no "good" statistical definition of a "good estimate" at this point. If you run across one, please let me know.
(2) That the INR produced by the Coag-Sense is highly correlated with the INR produced by the Lab (This might be a satisfactory definition of a "good estimate" depending on what the regression equations say) - and
(3) That this value is of such a quality that the Health Insurance company cannot refuse to discuss my INR and adjustments needed if any with me.

Roche and Coagusense stake their Meter business on the continued, constant accuracy of the meters and strips. The meters have also gone through FDA testing for accuracy. Personally, with the awful results that I've gotten from labs recently, I prefer to trust the meters more than I do the labs.

-- Based on the medical studies I have read to date I believe that the CoaguChek and Coag-Sense meters are reasonably accurate. I do not yet know how repeatable and accurate the Coag-Sense is > FOR ME<. I hope to develop that information after I become better at my pokes with my Lancet.

-- My health insurance lab does not charge me for the testing or the consulations. I have had very good and consistent results from them. I just want to be able to travel freely and get far fewer blood draws with confidence that I know what my INR is between blood draws.

So - take a deep breath - and another - and be comforted in the idea that a) INR results aren't precise, b) results appear within a range - usually within 20% of 'accurate', and c) your meter doesn't need anything done to it to improve its accuracy.

-- I quite agree with you except for the need for a deep breath. I use "The Relaxation Response" technique developed by Herbert Benson. As a result, I have a much lower then normal blood pressure. The book is 200+ pages but the actual technique is one page.
(A) the doctor who came up with the correlation between the Coag-Sense, the CoaguChek and the University Hospital Labs gave me a much longer lecture then you did on the factors causing imprecision / inaccuracy of the INR.
(B) I have been reading your, Pellicle's and others posts on How INR is measured. Range or Measurement Error is inherent in the current "definition"(s) of INR.
(C) Unfortunately, the main thing my meter needs to improve its accuracy is better handling of the blood draw by me. I am human and not robotic. I will get there eventually but only with a lot of pokes. Hence, my calling myself ScribeWithALancet.

(BTW - if you have a Coag-Sense, I have extra strips that I would like to sell)

Walk in His Peace,
David
ScribeWithALancet
(and lots of pokes)

 

[pellicle]

Thank you for the useful information. Do you have a link to the report that you took the table from

here is my copy of the original document:
https://www.dropbox.com/s/akjzipth7qck2bv/Accuracy-and-precision.pdf?dl=0

 

[tom in MO]

My insurance company is a HMO. It has both labs and coumadin specializing pharmacists. My HMO does not charge me for either the blood draws nor the INR tests using the blood draws nor the consultations with their Anti-Coagulation pharmacists.

Thanks for the response, I understand now. Good luck. They probably get paid every time you step foot into the HMO, thus they don't want you testing at home since it would lower their cash flow. There is probably an internal procedure against it.

I am just trying to make my health insurance company like letting me march to my own drummer (a Coag-Sense) when I am on travel or on a multiple week absence from the blood draw lab.

If you have your own meter and your own strips, when you travel, you can do your own tests and just not tell Most clinics are happy with a once a month visit.

 

[Protimenow]

Scribe -- there's one assumption that you're making that throws your whole plan off -- your assumption that labs get it right. I've had a lot of problems, with a number of labs, over the years (and four or five in the last 12 months) that return readings that are quite wrong. I've gone to the trouble of going to more than one lab, within hours of each test, and getting different results.

Using a lab result as a target for matching your meter's results to is absolutely wrong. Personally, I've come to trust the meter before I trust a lab - and I don't look for exact matches between tests (even seconds apart) to assure good technique or accuracy. I think you're chasing a moving target.

As far as a manufacturer changing the supplier for its reagents - this may not be a big deal. If Coagusense (the company, not the meter) has been using the 'same' reagent for ten years, what you may not realize is that the 'reagent' in each batch may have different reagent values -- and the code on the strip tells the meter what factor to divide the prothrombin time by in order to calculate an INR. The 'reagents' may be the same, but the value of the reagent changes from batch to batch. If Roche changed its supplier of reagents, they're very careful to test the strips before creating a chip to include with the manufactured strip.

Man, you're really overthinking this if you plan to run one or more daily tests - running through a box of strips in a month. I don't think that any amount of practice perfecting your technique will bring you to a point where you can get reliably repeatable results.

(I ran through many strips many years ago, after a serious of wrong results from my InRatio meter (consistently 2.6) caused me to get a TIA. In the hospital, my INR was 1.7. After that, I went on a quest to find the meter that I trusted the most. I tested with a Protime and Protime 3, Inratio and Inratio 2, Coaguchek S and Coaguchek XS, Coag-Sense, Hemochron (at an anticoagulation clinic) and more than one lab. Testing wasn't done daily, and I didn't always do a lab when I was comparing meters). My goal was to find the meter that I put the most trust into.

I ruled out the Protime and Protime 3 meters - they were accurate, but the strips required refrigeration, and they were kind of a pain to use - and the supplies were becoming increasingly hard to get. I gave the InRatio units a fair test - but, in spite of the stroke that the original meter caused, I still tested it; knowing that other meters should be more accurate. The InRatio were not accurate enough to trust.

The Coaguchek S was discontinued, so it had to be ruled out. The CoaguChek XS was usually higher than the lab results and, if my INR went above 3.5 or so, it had the same issues with values that were higher than expected as the InRatio had. I ruled it out as a first choice because it was too high when the INR was high (as reported in literature), and a bit high when the INR was lower.

The Coag-Sense didn't have the same error when blood INR was high that the CoagChekXS and InRatio did. No matter what the values from a good lab (UCLA clinic lab) were, the Coag-Sense was close, if not exact.

In many cases, for INRs that were in range, an average of the Coag-Sense and CoaguChek XS was almost the same as the lab values. )

I won't go further - this was just an explanation of the reasons that I had , some years ago, for running through a lot of strips.

Unless I've made a change in supplier for my warfarin, or I'm curious about any effect that greens from the day before may have had on my INR, I usually only test once a week. In most cases, if I've had an entirely unexpected binge on greens, I know that two or three days with an INR near 1.0 can be resolved in a few days just with normal dosing. It's not a big cause for concern.

Also - K2 has minimal or no impact on your INR - it's K1 that interferes with the clotting cascade. I've been taking K2 for more than a month - I've upped my dosage from 7.5 mg to 8 mg, and stay in range - about 2.6 - 2.7.

Some recent thinking about K1 is that taking it will help stabilize INR - it just means that the warfarin dose may have to be increased to accomodate for the effect.

Whatever method you use to relax is fine -- just don't go nuts trying to find an exact match to an elusive (or unattainable) target.

 

[Mercia]

I was using the CoaguChek XS from Roche for about 4 years with no issues after the recall from Alere Inratio2 meters.
Currently using CoagSense meter, for the last couple of months with some concerns - although the test strips is not as time sensitive, the sample transfer tube and process seems to be very sensitive to time - specifically the time it takes the user to fill tube with blood sample size. If you take to long, the unit reports crazy high INR results - which requires a retest. Not sure if this is known by all users, as I didn’t see it in any documentation prior to customer service from MDiNR telling me this.
There is also seems to be a firmware or SW issue which reset units back to default setting when used with battery only - so I currently need to keep my meter plugged into power to keep all my user setup.

 

[Protimenow]

You're probably using the PT1 - the original Coag-Sense meter. This is the one that uses AA batteries or a power supply. This is the meter with the monochrome screen. I've used mine for years, and although I now also have a PT2 (the new model), I still use both.

If the memory on the meter resets to default, be sure that you've got fresh batteries in it. Mine used to give me an error when the batteries were too low to run a test. When you replace your batteries, the clock may need to be reset - but test results should still be on the meter. Although you mayneed to reset the clock, the results should still be there. Pressing the Memory button should give you results from your tests. If the meter loses the results (in addition to time and date) - there's a definite problem, and you may want to contact the manufacturer. (I have a spare meter, barely or never used meter, if you're interested in it). (FWIW - the CoaguChek XS will also reset time and date if you take too long to replace the batteries).

As far as sampling issues - this happens to me extremely infrequently. Both the Coaguchek XS and the Coag-Sense meters require a drop on the strip within 15 seconds of making the incision. After that, blood may start to clot. After that, you'll get the odd results that you mentioned.

Although the Coag-Sense strips can be exposed to air after opening the pouch - perhaps even for a few hours in a dry environment or maybe longer in a sealed bag - they still require blood soon after incising your finger.

Are you using the new transfer tubes? (These are thin capillary tubes with a black plunger).
Are you using the right lancing device? Lancets for diabetic testing DO NOT get a large enough drop. I'm assuming that, since you've been testing for years, this isn't an issue, but I still wanted to ask.

The way that I test with the new transfer tubes is to:

1. Prep my hand. I often run it under warm water, to get more blood flow into my hand. Sometimes I'll swing my arm like a propeller to get more blood to my fingers. While the strip is warming up in the meter, I squeeze at the base of the knuckle below my fingertip, making sure to pool blood into the fingertip. Pellicle sometimes uses a wrap or two of dental floss around the knuckle to help the blood to collect in the fingertip.
2. I already have the transfer tube ready to use, and incise my finger.
3. I squeeze the fingertip slightly to get a large enough drop to form (you may not need this if you use floss to help collect the blood).
4. I take the transfer tube, holding it horizontally next to the drop. The capillary tube draws the drop to the white line on the tube. If there's not quite enough blood, I squeeze the fingertip a bit more, and finish drawing the blood to the white line.
5. I then touch the tip of the tube into the well on the strip. Sometimes, it'll touch the spinning wheel in the strip, confirming that the tube is in the right place. Pull back slightly if it's hitting the wheel, press the black plunger, and the blood will be deposited into the strip.

Just wait a minute or less (usually less) until the clot forms and the meter gives you a result.

If you have problems, call Coagusense. The number is on the bottom of the meter (I think), it's on the website. They also have instructions on the website. I've called them with other questions, and they're happy to walk you through how to do a successful test.

It's in their best interest for you to be able to easily, successfully, (and maybe even enjoyably) run an INR test. (And if there are problems with your meter, they'll be able to tell you). You shouldn't be wasting ANY strips as a result of testing problems.

If you have any questions, you can also send me a private message.

 

[Mercia]

My tester version seems to be the new one - no batteries to replace just power charger to recharge. Color screen with WIFI, USB port etc. My transfer tubes is likely also newer style as per your description. Luckily I get my supply covered thru Medicare/ Medigap insurance at no extra cost. i will definitely contact Coagusense to request in resolving my meter concerns. Thanks

 

[Protimenow]

When you mentioned battery, I thought you were talking about replaceable batteries.

Yes, you have the new model.

I had an issue with it, too -- you have to be careful when you turn it off. If you don't hold the power button, it may go into standby - which is good for clinics because it starts right up - but bad for users like you and me (the battery goes dead after a few hours).

You have to hold the power button until the meter shuts off. It can go for many weeks before requiring a recharge.

If you have access to Wi-Fi, the meter will download a firmware update. The update is minor - I've installed it - and it comes on the next time you restart the meter.

Again -- if you're not careful that you hold the power button down until it turns off, the battery may go dead. You may have to reset the clock if it does this. But nothing is lost -- except time and date.

If you're otherwise able to easily run tests, this bit of knowledge may be all you need...

 

[Agian]

Aww, you INR nerds. I love you guys.

 

[Protimenow]

Hey, Agian -- it's all about getting a good test. (Not necessarily within range, but at least one that can be trusted). I like that - 'INR nerds.'

 

[ScribeWithALancet]

here is my copy of the original document:
https://www.dropbox.com/s/akjzipth7qck2bv/Accuracy-and-precision.pdf?dl=0

Pellicle,

Thank you for the link. Initially, dropbox did not work. I used the filename to search for it and found the pdf on an Italian Roche web site and later on a couple others. After I found those, dropbox allowed me to download it but not to save it as a pdf. I finally got it saved as a pdf. It provides good information that I need and explains the functions of reagents fairly well. Thank you for pointing it out to me as it greatly helps in understanding the functions of reagents in the INR systems.

I will use it in explaining the why of Dr. Johnson conducting regression analyses comparing the University of Utah CoaguSense and CoaguChek XS devices with their Stag Lab INR laboratory device for blood draws.

It always amazes me how well regression analysis can work when matching data is available within the ranges for two or more data sets & techniques and how often people try to use it to project answers for data ranges that they do not have matching data for. Technology keeps improving but human behavior keeps pretty much the same.

People also do not question sample sizes (or whether the full sample was used) in regression analysis either in environmental or medical research.

Walk in His Peace,
David
ScribeWithALance

 

[ScribeWithALancet]

Scribe -- there's one assumption that you're making that throws your whole plan off -- your assumption that labs get it right. I've had a lot of problems, with a number of labs, over the years (and four or five in the last 12 months) that return readings that are quite wrong. I've gone to the trouble of going to more than one lab, within hours of each test, and getting different results.

Using a lab result as a target for matching your meter's results to is absolutely wrong.
...

Actually, when you say "your assumption that labs get it right." is close but not quite accurate. My assumption is that the lab's results can be closely correlated to my Coag-Sense meter meter results. This was done by Dr. Stacy Johnson of the University of Utah in three different papers using one Lab system and two home POC INR meter systems. He was able to achieve a very high correlation within one range and a good correlation within a second range and prove that results were usually not good in a third very high range. He did not assume the lab INR was right or that the meters' INRs were right. He did calculate that they achieved statistically highly correlatable results. Dr. Johnson warned that the whole system for calculating INRs is, as you and Pellicle say, rubbery. He used different words that amounted to the same thing.

You mentioned "Also - K2 has minimal or no impact on your INR - it's K1 that interferes with the clotting cascade. I've been taking K2 for more than a month - I've upped my dosage from 7.5 mg to 8 mg, and stay in range - about 2.6 - 2.7."

Unfortunately, for me, this was not true. I got dropped from 3.0 to 2.2 when I took some K2 pills. I am now building up using 0.1 mg K2 pills. Given how metabolism can vary, it could have been the K2 or it could have been a random change in my metabolism. I made the mistake of following my Coumadin Pharmacist and significantly increasing my dose of Coumadin at the same time I stopped taking the K2. My INR jumped to about 4.3. I have since switched Pharmacists. Hopefully, I can build up to your level. K2 drives the body's system for moving calcium from where it should not be to where it should be. My teeth have gotten noticeably better since I started eating grass fed organic eggs, meats and heavy cream that have naturally occurring K2 in them (3 1/2 years ago). Unfortunately, since I cannot eat a consistent diet of K2 (The US Dept of Agriculture defines organic as 100+ days of grass feeding per year - a very "rubbery" amount) my estimate of K2 from Food is from 25 to 50 mg per day. However given that it may be entirely non grass fed it actually ranges from 0 to 50 mg per day. My body seems to be sensitive to K2 so I need the meter's reading badly.

It was interesting to read that one of Coag-Sense's study showed a repeatability of the reading to within 0.2 units of INR for the majority of their collections and a repeatablity to within 0.3 units of INR for the majority of the remainder. Unfortunately a couple were around 0.5 units. The study showed a high degree of correlation between the Coag-Sense and the lab technique they were using in the test. This was similar to the findings that Dr. Johnson found for both the Coag-Sense and the CoaguChek - a high degree of correlation but NOT a match. The implication to me is that if my readings are consistent with my previous reading that I should probably not have to worry much and that if they are trending up or down, I should start paying attention.

You mentioned "Some recent thinking about K1 is that taking it will help stabilize INR - it just means that the warfarin dose may have to be increased to accomodate for the effect." My first Coumadin Pharmacist thought this way back in 2004. He had me build up to 2 ounces of spinach (306 mg of K1) per day. My variation in INR almost vanished until I started eating organic food several years ago. For me, it seems to help stabilize my INR. As they say, Your Mileage May Vary. As you mentioned, I did have to increase my average dose to my now 13.5 mg of coumadin a day. However, my INR has stayed in the 2.5 to 3.5 range most of the time. My then Coumadin Pharmacist said I was the most stable of his patients. None of his other patients was willing to eat a steady diet of greens. We picked 2 ounces because a lot of fresh spinach was available in 4 ounce and 6 ounce packages and easy to divide up into 2 ounce chunks and eat before it spoiled.

I subsequently purchased a chemist's scale and weigh the greens. This allows me to eat a wider variety. Stil approximately 300 mg of K1 per day but less perfectly. We are using the Dept of Agriculture's estimates for the K1 content. While that is probably correct on average, it is probably not "accurate" for any individual day". The change to a variety of greens did not seem to affect my INR until I went on Organic food - see above comments on K2 which may or may not be correct.

In my psoriasis magazine, there is a section called "It works for me" which comes with that same warning. About one thing in ten they mention works for me. I still try a lot of them because you never know. Vacation trips to Washington State, Iceland and Israel (The Dead Sea area) are out of my price range but have helped a LOT of psoriasis patients. Is it the geologic environment or the human relaxation environment or something else - who knows?

Thank you for your extra advice on how to do the blood draw. I do have the newer Coag-Sense and the newer transfer tubes. The Thermophore Moist heat pad for 3 minutes helped a lot. I am after consistency and minimization of variation not perfection.

Would you please consider posting similar advice but on what data and analytics might be useful in doing the spreadsheets? Mine is probably too simple. It just has date, time, INR, PT for the Coag-Sense in the first half of the row and in one set of columns and a similar set for the Lab's values on days when I draw both in the second half of the row. No statistics at this point. I apologize for asking if you, Pellicle or someone else has already posted this.

Walk in His Peace,
David
ScribeWithALancet
(and lots of pokes)

 

[pellicle]

Hi

I apologize for asking if you, Pellicle or someone else has already posted this.

absolutely no reason to apologize, searching this sort of thing is fraught ... there's either no returns or pages worth.

My approach is more goal oriented, and my goal is simply keep my INR within the range of 2 through to 3 (so I target 2.5). I keep only the following data:

• measured INR (weekly)
• the date of the measurement
• dose for the week ahead

In the past I used to compare my lab draws to my own measurements with my Coaguchek XS which I began doing every test, then after dropping the lab (I have no such impediments to doing what ever I want as you appear to) I began getting a lab draw every 3 months, then 6 months and now its been a few years I think.

My lab INR was seldom more than 0.2 INR away from my XS.

I do some other calculations on that data which guides me, but that's something I keep under my hat a until I determine if I can sell the idea or publish my research (depends which avenue seems more fruitful).

I don't see there's any benefit in over complicating things.

 

[Protimenow]

As Pellicle said, there's no need to apologize.

I've been keeping my spreadsheet of test results since April 2009 - the data fields are fairly simple: date, time, meter (or lab) used (because I've tested at least 8 meters and a number of labs and want to identify each source of results), dose, and comments - which include any factors that may have an effect on INR (and other things).

For a while, when I switched between CoaguChek XS and Coag-Sense, I used a different color for the CoaguChek XS, just to make it easier to tease out results. I haven't done analysis on the data, aside from comparisons.

Now - my statement about not trusting labs was relative. When the InRatio gave me results that differed from labs, InRatio's support people told me to 'trust the labs.' I have, most of the time.

But I've also gotten really crazy results from a few labs. One of the recent ones was a 5.2 - my meter was consistently giving me 2.9 - for many weeks. I repeated the test, with the same result. I tried other labs - with results much closer to my 2.9 than the lab's 5.2. I reported this to my doctor who thanked me - he had another patient whose INR was always stable and in range - and the lab reported 7.1. This spared that patient from an incorrect stop of warfarin or other rather drastic, unnecessary, and potentially dangerous change in dosing - and made it clear that the lab was messing up.

I used to have complete confidence in lab results - based on some rather scary results coming from a few labs, I've chosen to give the meter's values more weight than the labs.

(An executive at a meter company complained that 'they always blame the meters.' I don't anymore.)

If you find a lab with values near those of your meter, you're doing okay. The labs my doctors use aren't that consistent and haven't earned my trust. This is one of the reasons that I trust my meters. (I now have three Coag-sense meters - and sometimes use the PT1 and PT2 for comparison to each other. They're consistent with each other. I've also tested different batches of strips and they, too, are consistent with other batches.

If I ever come into a supply of CoaguChek XS strips, I'll add this meter back into my occasional comparison methodology.

As Pellicle advised - don't overthink this. Testing is simple. If you find a good lab, occasional comparison doesn't hurt.

 

[tom in MO]

Hi



absolutely no reason to apologize, searching this sort of thing is fraught ... there's either no returns or pages worth.

My approach is more goal oriented, and my goal is simply keep my INR within the range of 2 through to 3 (so I target 2.5). I keep only the following data:

• measured INR (weekly)
• the date of the measurement
• dose for the week ahead

In the past I used to compare my lab draws to my own measurements with my Coaguchek XS which I began doing every test, then after dropping the lab (I have no such impediments to doing what ever I want as you appear to) I began getting a lab draw every 3 months, then 6 months and now its been a few years I think.

My lab INR was seldom more than 0.2 INR away from my XS.

I do some other calculations on that data which guides me, but that's something I keep under my hat a until I determine if I can sell the idea or publish my research (depends which avenue seems more fruitful).

I don't see there's any benefit in over complicating things.

Might want to record when you change your batteries. The meter can get wonky before it says it needs to be fed new batteries.

 

[pellicle]

Might want to record when you change your batteries. The meter can get wonky before it says it needs to be fed new batteries.

Interesting, are you meaning the XS? How have you determined this?