The two 'H's - and INR results

[Protimenow]

Probably unlike nearly all of those on this forum, I am interested in testing with more than one meter. When I was able to get a monthly blood draw, I compared my results to a hospital lab.

My weekly routine usually involves a test using the Coag-Sense meter - which performs a test that actually measures the amount of time that it takes for a clot to form; and a CoaguChek XS. I've had the Coag-Sense since early March. I got a CoaguChek XS in mid-April. The two meters have never matched. The XS always reported a higher INR.

To make this more interesting, tests made with the CoaguChek XS and InRatio 2 meters have so far been within 0.1 INR of each other. The agreement of the two meters makes me suspect that a) the meters are both 'correct', or b) that the meters are both equally influenced by something that would make their results equally incorrect.

This brings me to H&H. This term refers to Hematocrit and Hemoglobin. Both factors, if somewhat far from normal, can result in wrong results in both the InRatio and the CoaguChek XS (this is according to each meter's literature). In the past, I've noted that, as long as all meters put me in range, I'm less troubled about the meters not being in agreement than I would be if one of the meters put me below 2.5.

I ran a set of controls on the Coag-Sense last Friday, after getting a 2.8 on the Coag-Sense, and a 4.0 on the CoaguChek XS. (I followed this a few minutes later with a 4.1 on the InRatio 2). The controls on the Coag-Sense certainly suggest that the result it gave me is accurate.

So -- I have to wonder - could my Hemoglobin or Hematocrit be enough out of range that the XS and InRatio results are reported to be higher than they really are? When I can, I'll get a CBC to rule possible anemia - or worse - out.

I have to wonder, too, that if my H or H are out of whack, what happens to others with Hematocrit or Hemoglobin issues whose reported INRs are actually higher than actual?

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I wonder, too, if any of you may have been told by your doctors, anticoagulation clinics or ??? that your hemoglobin or hematocrit values were off AND that your INRs on an XS or InRatio may have been impacted by this.

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If/when I get my blood tested, I'll let people know. (I really wonder if the difference between testing protocols - and if the reported insensitivity to H&H that the Coag-Sense design has built in - may have suggested anemia or other issue)

 

[pellicle]

Hi

When I was able to get a monthly blood draw, I compared my results to a hospital lab.

which is a good thing ...

To make this more interesting, tests made with the InRatio and InRatio 2 meters have so far been within 0.1 INR of each other. The agreement of the two meters makes me suspect that a) the meters are both 'correct', or b) that the meters are both equally influenced by something that would make their results equally incorrect.

your assumption seems valid, but I didn't see the lab test results in there ... without such you have hypotheses but no attempt to validate your questions. Posing questions is interesting, answering them is the goal is it not?

I ran a set of controls on the Coag-Sense last Friday, after getting a 2.8 on the Coag-Sense, and a 4.0 on the CoaguChek XS. (I followed this a few minutes later with a 4.1 on the InRatio 2). The controls on the Coag-Sense certainly suggest that the result it gave me is accurate.

nor here. You say "controls" but what do you mean? Seems you just took some samples of output. I know you desire to produce helpful input here, but your methods need to be a bit stricter.

I have to wonder, too, that if my H or H are out of whack, what happens to others with Hematocrit or Hemoglobin issues whose reported INRs are actually higher than actual?

a good question, but how do you know what your "actual" was?

If/when I get my blood tested, I'll let people know

I would think that without such information presented at the same time it makes this posting nothing more than "casual interest in how variance can exist between machines"

it seem to me to add little of value without a cross reference to a reliable standard such as a vein draw. Any of or all of these machines could be out and the results could be anywhere.

Further have you compared each in reading to an un-anticoagulated person for "control"?

 

[Protimenow]

Pellicle:

The reason that I assumed that the InRatio and CoaguChek XS meters were either equally accurate, or equally inaccurate was because a) the results have been very close to each other and b) the results deviated considerably from the possibly more accurate Coag-Sense. My major problem with determining which assumption was correct was my inability to get blood draws to compare to the results from the meter. If I had been able to get a blood draw at around the same time as these three tests on meters, I would have reported the results of the blood draw.

I've been able to make lab comparisons a number of times. On December 26, 2012, the clinic's Hemochron and my ProTime 3 BOTH reported a 3.4. For some reason, I didn't test with the InRatio 2 at that time. (I didn't have the XS or Coag-Sense at that time). On March 1, the lab gave me a 2.7 -- right in the middle between a 2.5 reported by the Coag-Sense and a 2.9 from the InRatio 2. On March 28, I got similarly confusing results. The lab reported a 2.7. Coag-Sense said 2.3, InRatio 2 said 3.0, and ProTime 3 said 2.9. The blood draw on 3/28 was my last blood draw.

When I referred to controls for the Coag-Sense meter, I was referring to special quality control test strips that were made for the meter. I ran a High Control and a Low Control, and both control strips passed the test. This would lead to the assumption that the batch of strips - and the meter - were accurate.

In the past few months, the gap between Coag-Sense and InRatio/CoaguChek XS has widened, making me wonder if Hematocrit of Hemoglobin irregularities may be at play here. When I can, I'll see about getting a vein draw - but these, too, may often be more 'art' than 'science.' A CBC - which tests the H&H and other factors may help to dispel he concern that the electronic meters (InRatio and CoaguChek XS) may be reporting higher than actual for medical reasons.

And, yes, this does reflect interest in the reasons that there is variance between the machines. However, if this difference from machines of one type and those of other types -- and these differences can be suggestive of blood issues - this may be worth exploring further. Hell, if there is an actual explanation for the differences that can be attributed to blood irregularities, occasionally testing with two different machines may even be considered diagnostic.

 

[pellicle]

Hi

As I see it the past similarity in readings is just that: a past one. Especially when you are discussing identifying differences with current results as compared to the results of now.

When you are trying to work out why there is a variance which wasn't there before it becomes clear that you need to go back to first principles again and not rely on assumptions. Otherwise you will just be chasing your tail.

 

[Protimenow]

At first thought, I didn't think that I assumed anything. However, I DID assume that the performance of the meters hasn't changed over time. I've assumed that because the values reported by the InRatio and the CoaguChek XS have remained almost identical, that the process that they use to determine INR has not changed, and that their results were consistent, based on those processes. I don't think that either one has 'gone bad' or that the strips have somehow changed during this period.

I was assuming that the Coag-Sense may not have been accurate, or may have changed in accuracy (or something), which resulted in the amount of difference from the InRatio and the CoaguChek XS results increasing. The quality control tests, designed for this meter, and run as directed by the manufacturer, strongly suggest that this meter is passing QC and that the strips are okay. This brings me back to the question of why the results vary so greatly.

I'll do another test -- I have Coag-Sense strips from two different lots. I'll see if the strips from the two different lots report the same value when testing blood drawn from different fingers, a few minutes apart. It'll be interesting a) if the results don't match and b) if the results from the newer lot are closer to the ones from the CoaguChek XS than the current lot reports.

 

[pellicle]

Hi

I am not suggesting that the strips have gone bad. I am suggesting that something may have changed(perhaps in your blood as you suggest. This will perhaps change the dynamics of the reactions (as you seem to be conjecturing) and therefore change the results.

I see what you are trying to do and all I am doing is making the observations that my supervisor would have made in my research in identifying flaws and hidden assumptions. You could also do well to layout your writing so that it doesn't read like following spaghetti. That is if you actually want others to read it. Think about how often people misunderstand things and ask yourself if you are helping that process.

 

[Protimenow]

I write for a living. I've worked in medical research.

I didn't realize that my writing was spaghetti.

I didn't sense any attack from you.

Perhaps I'll take more time to write in shorter sentences, with shorter streams of thought, and with fewer parentheses.

What I plan to do is test my blood on the Coag-Sense with two different batches of strips and see if the values are close. If not, I'll test with the XS and see how it compares to both lots of Coag-Sense strips. I'm trying to determine if the differences ARE due to problems with MY blood that could throw the InRatio and XS values into higher than actual values.

I'll report on this later. (I plan to get a CBC blood test in the near future to rule out the potential H&H issues).

 

[pellicle]

I didn't sense any attack from you.

That's good because that was not my intention

 

[Protimenow]

My next steps are obvious: Get a blood test. See a doctor.

Last night, my INRs were so surprising - and covered such a range - that I used all four machines. Here are the results:

CoaguChek XS : 4.8
Coag-Sense: 3.5
InRatio: 5.2
Coag-Sense: 3.2
ProTime 3: 4.2

The first four tests were made within minutes of each other. The first test with the Coag-Sense was made with a SECOND drop of blood (although the instructions talk about a first drop, within fifteen seconds of incision). The second test with the Coag-Sense used a newer strip lot (both lots that I am using are at least a year from their expiration dates).

It's been well documented that at higher INRs (above 4.0), InRatio and CoaguChek XS report higher than actual - the difference between the XS's reported 4.8 and the InRatio's reported 5.2 is probably not that great and may be due to the documented over-reporting bias.

The general protocol for readings above 4.0 usually calls for a blood draw to confirm the value. According to what I was told by Coagusense a few months ago is that a clinic that uses other machines is USING THE COAG-SENSE TO DOUBLE-CHECK HIGHER RESULTS FROM OTHER METERS. It may be that my actual INR is 3.5.

I'm trying to make this clear, Pellicle.

The jump in INRs from last week:
Coag-Sense: 2.8
CoaguChek XS: 4.0
InRatio 2: 4.1

suggest that I may have double-dosed a day or so ago (although I don't think that I did). The 4.2 reported by the ProTime 3 even more strongly suggests that something's going on -- and it may just be an extra dose of warfarin.

Back to my original point:

I should get my blood tested. I should get a blood draw for an INR. I should get a CBC - and possibly more extensive testing - to see if my H & H are within normal limits. I should get medical input.

Unfortunately, in the United States, there's no government health care. I have no medical insurance. I will be able to get the blood test without a doctor's prescription -- but then what?

If my tests show problems, I'll take it from there.

Returning to my original reason for this thread -- I proposed that a difference in INRs reported by Coag-Sense (which is reportedly insensitive to Hemoglobin and Hematocrit levels) and CoaguChek XS and InRatio (which CAN be influenced by Hemoglobin and Hematocrit levels) may be suggestive of blood issues.

Although I'm probably a monumental idiot for reporting on my own personal medical issues, I will probably report more once I get my blood results.

 

[Protimenow]

In earlier posts, I theorized that the relatively large differences between values reported by my CoaguChek XS (and InRatio) and the Coag-Sense meters may be related to problems with my hemoglobin or hematocrit. The results from a blood test that I had three days ago show that my H & H are within normal ranges (thank God).

I learned from someone at one of the meter distributors that the values reported by Coag-Sense are very close to those reported by the CoaguChek XS. It was suggested that my meter (which I bought used) may have damaged electrodes. I followed the cleaning procedures provided by Roche and cleaned the strip channel as directed. I don't think this solved the issue.

I may clean the XS again, not that it needs it. On Monday, I may retest my INR using the Coag-Sense and the XS and see if the gap has narrowed. If not, I may contact Roche and see what they suggest. (I have a friend who is a doctor, and he takes Coumadin. I'll see if I can test on his meter, and mine, and see if the results are far apart).

My suggestion -- although the InRatio and CoaguChek XS are both sensitive to H&H, it makes sense to compare the results to a blood draw just to be sure. Unfortunately, my lab doesn't do INR testing.

 

[Protimenow]

It's Monday. I have been taking some new OTC medications, based on recommendations related to my blood test results. I tested yesterday to check for any major changes in my INR that may have resulted from my added medications. (For example, my Vitamin D levels were low - I'm now taking 5000 units of Vitamin D; my total cholesterol is VERY low so I'm taking a fish oil capsule and eating more).

On the Coag-Sense, my INR was 3.1. The XS gave me a 3.9.

My wife saw me testing my blood and volunteered her finger for testing. She doesn't take warfarin. Her tests were both at the normal values for an non-anticoagulated person. (I was expecting to see more than 1.0 on the XS because it seems to be overestimating values -- of course, this may be related to how high ABOVE 1.0 the result is).

I will test at a friend's office, using his XS and mine, and strips from the same lot. This may give me some idea if there's an actual issue with my meter. It may also give me ammunition if I have to go to Roche for support.