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Re: [IP] Comparison of Lifescan One Touch Ultra to One Touch Profile
<My original post>
<Remember in comparing that the Profile is a whole blood meter whereas the
other two are plasma based. The plasma readings are about 12% higher than
the whole blood, so the Ultra (and Fasttake) should read about 12% higher
than the Profile.>
<Both meters are whole blood meters. The Ultra is programmed to adjust the
measurement to account for the erythrocytes and return a serum glucose
But I'll comment once more about reporting the relative accuracy and
precision of home test meters: it's inappropriate to compare one meter
against another for accuracy and precision. The purpose of meters is not to
obtain an exact measurement of either blood or serum glucose but to give
sufficient information to estimate insulin needs and to spot trends in one's
control. I want to emphasize *ESTIMATE* glucose needs. It's clear from all
the posts about what works when, etc., that neither bolusing nor basal rate
establishment is exact.
The precision level of these meters is such that it's entirely possible that
a Profile and and Ultra would be within the required standards and still
have the Ultra read lower than the Profile.
BTW, it's my understanding that the difference between blood and serum
glucose is closer to 18% - but I could be misremembering here.>
Thanks, Jim, for your post. My point in the section you quoted was that the
Ultra and FastTake give readings that are plasma-based, and thus should read
12% higher (you are correct that they all measure whole blood, but since the
Ultra and FastTake then convert to plasma-based, it is a distinction without
a difference for most of us). The original post did compare the two
different type of meters; that's why I responded. I continually see folks
compare their meters based on the two different systems, and I think it's
helpful to point out the 12% difference.
And it is 12%, not 18%--I quote from the Lifescan One Touch (Profile) test
strips: "laboratories using plasma or serum samples will produce glucose
results about 12% higher than your meter results."
I respectfully disagree with your (oft-mentioned) statement that "it's
inappropriate to compare one meter against another for accuracy and
precision." I understand what you are saying, and about the margin of error.
But I'm telling you that for a month I compared the results of the One Touch
Profile (3 different meters), Fasttake (3 different meters), and Ultra (2
different meters). In the beginning of the test period I noted quite a
number of discrepancies, but then realized that my technique was at fault in
using the two newer types of meters (pushing my finger against the strip
rather than letting the blood flow freely onto it). After that adjustment,
the results were amazingly consistent. I even used various bottles of strips
(with different codes). Perhaps all this is extreme, but for me the
(relative) accuracy of the meter was more important than the convenience. I
had to understand the relationship of the previous meter type to the new
one(s) I was thinking of switching to. In comparing two or three meters of
the same type for an extended period of time, I was able to gain a greater
level of confidence that these meters are accurate (and more accurate than
the "within 20% accuracy" advertised). I have also compared these meters to
the lab tests, again with very favorable results (<5% difference). I am
confident that the biggest variable in readings is our technique in applying
the blood, not the meters themselves.
I appreciate all your posts, and understand your points about accuracy, but
I really think that doing the type of tests that I did when switching meters
helps us to get a better understanding of the relative "accuracy" of the
meters as well as the effectiveness of our technique. So yes, I will
continue to compare...and I won't switch to a new meter just because of its
features unless I check it out myself. And in case you're wondering...yes,
my fingers get very tired of all this comparison testing, since I test 12x a
day anyway...during my "test" month my tests were far more often than that!
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