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RE: [IP] a1c/highs and lows

Catherine Popper [mailto:email @ redacted] wrote:

> > The a1c holds no water with me as far as I'm
> > concerned and is just a number
> > but my daily logs tell the truth.
> > -----End Original Message-----
> > 
> > I absolutely agree with you! Many doctors see that
> > great A1c result and
> > refuse to see anything else. 
> I'm starting to see that the A1C is yet another sloppy
> gauge docs use to try to wrap their brains around this
> crazy disease. I do think that it's useful to compare
> your own A1C's, even though in the past I've been
> mystified by good A1C's that don't seem to correspond
> to my BG logs. I read somewhere that though BG
> readings of >240 are discouraging, people who have
> these readings and correct them end up with better
> A1C's than people who don't test at all,) and worse
> looking logbooks. My control has been MUCH better on
> the pump even though I still have roller coaster days.
> I'll be curious (read: terrified) to see my A1C.

<Professional Mode = ON>

There are HbA1c tests and there are HbA1c tests.  The tests done in a
physician's office are usually a rapid test that has the same standards for
precision and accuracy as our own BG meters (approx. +/- 20%).

The "gold standard" HbA1c test is by a process called hemochromatography.
It's a moderate/high complexity test that (relatively speaking) not many
labs use.  Most of these tests are pretty close, although there are
differences between manufacturers.  

The HbA1c by hemochromatography is *the* prognostic test for likelihood of
complications, specifically diabetic retinopathy (which is what the DCCT
studied).  It is our personal meters that are the approximation.

Many docs will try to save costs by using either their own equipment, or a
lab that uses a less accurate and precise method for doing the test (this is
more likely a requirement of the insurance provider!).  A little research
would be appropriate to find out just what test method(s) are being used for
your records.  I think it's appropriate to insist that at least one HbA1c a
year be done by a good laboratory using hemochromatography methods - and
probably to insist that each year the specimen be sent to the *same*
laboratory to eliminate lab procedures and specific manufacturers as factors
in the variability.

Jim Handsfield, PhD, MPH
Division of Laboratory Systems
Public Health Practice Program Office
Centers for Disease Control & Prevention
email @ redacted / (770)488-8106
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