[This s the entry that I was going to have posted a little after
16:00 yesterday, but got rather dramatically interrupted while I was
typing the footnotes.]
Urgh. Really not feeling well. Did finally get a decent amount
of sleep in one day [Thursday night and Friday morning],
but at inconvenient times (of course *pout*)
and broken up into smaller chunks. Anyhow, I am currently feeling
a lot of pain in various places and having trouble with stairs
[even more so now], but
this [was] the most awake I'[d] felt all week. It [felt]
like I almost [had] my own brain again.
One of the sleep-chunks ended with a dream about calculus. About
having a calculus test in the morning that I wasn't prepared for and
was worried about oversleeping and missing. Except that evert few
minutes of the dream, it switched whether I was student or teacher,
worried about taking the test, or about being there to give the test.
And I was in a different house than mine, but the roof leaked there
too.
A while back an airline lost my mother's glucometer and her
insurance gave her a different brand when they replaced it, so
she had a lot of no-longer-the-right-kind of test strips
which are the right kind for one of my meters. Thus, at the
moment, I've got more strips than I need, some of which have
expiration dates a decent ways into the future, some expiring
soonish, and many past their expiration dates. I've been wondering
just how bad the 'expired' strips are. Sometimes when getting
to the end of a vial of still-current test strips I'll crack open
a vial of expired ones and compare results on the same drop of
blood, and if they're close, I'll go ahead and use that batch of
old strips next. So far I've only once gotten a result far enough
from the result on a not-expired strip to convince me to set that
expired batch aside.
But then I started wondering how repeatable the results are
anyhow, and how far apart the numbers have to be to indicate
that one of the strips isn't right. Alas, probability &
statistics is my weakest topic in math, so I don't have an
intuitive grasp of what the numbers I can find on the web mean,
but with this huge surplus of test strips at the moment I could
do my own experiment to get a rough idea with my own live data.
( experiment and raw data )
Now this is, of course, too small a sample to draw really
meaningful conclusions from, but it does suggest a couple of
things for me to keep in mind when I try to make sense of
how my body reacts to different foods, or wonder why my morning
reading is a little higher than usual. Mostly that "a little
[higher|lower] than usual" could just be expected fluctuations
in the instrument rather than meaningful differences in my
blood sugar level. I'm not at all surprised at the performance
of the expired strips, as my guess was that the expiration dates
are conservative limits on how long the manufacturer is
sure the strips will be good for, and any one vial of
strips may or may not still be reliable for quite a
while longer. (So I'll still need to compare results from
expired strips I'm thinking of using to not-expired strips
to determine whether that vial is still useable or
not.) The second test with a strip from that batch with
calibration code 17 was from the vial I mentioned earlier as
having set aside because it produced a measurement out of line
with a current strip a couple of weeks ago. It looks like
maybe those strips don't need to be tossed out after all.
Anyone is, as usual, welcome to comment on this, but folks
with greater Statistics-fu than I have are especially invited
to do so. As are folks who actually know stuff about these
meters, how they work, and the published performance stats.
[*] If anybody's wondering: the easiest to use
glucometer that I've seen so far (not that I've seen all
that many so far), is the Bayer Ascencia Contour. It also
works with a particularly small drop of blood, though I
think the Accucheck Aviva may have it beat slightly in that
regard (both take noticeably less blood than other meters
I've used).
[**] So far, in myself, I've seen blood glucose levels
ranging from 59 to 190 mg/dL, with readings above 160 being fairly
rare. So I should repeat this experiment some day when my sugar
is up in the 160-180 range, and then talk someone else who routinely
gets higher numbers into doing the same experiment above 200, just
to see whether the results diverge more when the numbers are
higher. Or I could just get distracted by some other project...
[***] Ever notice that the meters' instruction booklets
all give guidelines for how often you should check the meter's
calibration with the test fluid (which itself becomes unreliable,
according to the manufacturers, three months after you first open
the bottle), but insurance plans that supply test strips and
lancents don't include calibration fluid? (And some drug stores
have to special-order it?) I'm seeing a disconnect here.