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Re: [IP] Meters Differ in readings

At 11:33 AM 7/31/03 -0400, you wrote:
 >Why do all (3) of my meters (plasma) show a difference in the readings?  I
 >have (3) One Touch Ultra's, bought within a short time of one another.  They
 > read out as 150/190/210, with the same drop of blood, at the same time. 
 >a big difference in these numbers.  I have used the solution that comes with
 >the Ultras but that does not do anything.

 From the archives, courtesy of Jim Handsfield, who works for the CDC

I'll put on my professional hat for this one.

Federal regulations require all waived laboratory tests, which includes 
home glucose test meters, to achieve certain standards before they may be 
marketed. There are two basic standards: 1) the device must be simple 
enough so that the instructions may be read, understood, and followed 
without assistance by someone with a seventh grade education; and 2) the 
device must have results that are within 5% of a standard equivalent 
laboratory test (moderate complexity) 50% of the time. That precision level 
is approximated as +/- 20% of the laboratory tests (not another meter).

If you compare meters against each other, the ranges of precision have to 
be compounded (IOW, the precision ranges will be quite a bit greater than 
+/- 20%) to get the appropriate range because they are not independent 
events. It is inappropriate for that reason to compare the results of home 
test meters against each other. The only reliable test is to do your own 
test at the same time you are having blood drawn for a laboratory glucose 

These standards were/are developed by the Standards Branch of the Division 
of Laboratory Systems of CDC where I work. I have provided statistical 
support for this branch on several occasions.

If you believe your meter is not sufficiently accurate or precise, contact 
the manufacturer. They generally have very liberal replacement policies. 
But giving comparisons against other meter results won't suffice.

Jim Handsfield
email @ redacted

The opinions expressed are mine and do not necessarily represent those of 
my wife who runs our house and makes more important decisions than I do.
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