meter discrepancy

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Mindy & Max

Mindy & Max

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So...I've done all of Max's tests with a Maxima AST. We're getting consisten numbers in the 200s now...hoping to do a curve this weekend before upping his dose.

Anyway, last night in the mail I received a OneTouch UltraMini meter (signed up for a "freebie" before finding out it would take 3-4 weeks to arrive). I decided to try it out to see if I liked it better than the AST (it is easier to hold on to and it doesn't beep--big plus for Max who is noise-sensitive and skittish--but it takes a much larger sample of blood and the strips cost twice as much). It was PMPS+3, and the reading was 338. I tested the same blood spot with the AST right after that, and it read 273. That's a 60-point difference! I did a control test on the AST, and it was reading in the normal range. No control solution came with the OneTouch, so I couldn't do that one.

How do I know which one is right?
 
The normal accuracy range of these meters is +/- 20%, which is a pretty broad range at higher numbers.

If the "true" blood glucose is 300 ---- the meters can read anywhere from 240 to 360 and the reading is "Accurate" enough to keep humans and kitties safe.

So -- your readings of 273 and 338 are within the accuracy range of the meter.

Lower readings are more critical -- and the meters will read closer to the "True" number

If the "true" blood glucose is 60 (normal) --- the meters can read anywhere from 48 to 72

In order to make these meters inexpensive enough for everyone to have one or several -- they make them "good enough". The super-accurate test devices run in the $$$thousands and only labs can afford them.
 
Thanks for the info, Phoebe! I figured there was a "range", but didn't know what it was. I figured it's probably more important to stick with the same meter than the actual number, especially for long-term data collection, but wanted to check it out anyway.
 
I know nothing about the Maxima, OTU user here and not the mini, but if the Maxima gives you and average over the weeks of testing you could then run a fructosamine and see if the meter is giving you the same. I did that when I had used the Elite XL on Hope. Showed it was not the same as the Fructosamine test. Then I went back to my OTU and used it for both Hope and Mishka. Fructosamine came back in range of "Excellent". Also, read your manual again.....majority of the meters you can turn the beep off.
 
I have seldom found a case where a +/- 10% difference in readings has affected my choice of when/how to shoot insulin or feed. Rough is really good enough, so long as it's consistent. I'd stick with whichever meter is most convenient and learn to read your cat's reactions to the numbers that meter gives.
 
Just FYI, this is anecdotal, but the One Touch seems to me to be on the high side for higher readings. Again, within the range of accuracy but on the high side. There is a difference between accuracy (how close to the true number will the meter read) and reproducibility (how likely are you to get the same number on the same meter from the same blood sample).
 
Lydia, I've know for years that the OTU and even the ACAdvantage will read higher once you get into the 400's. When it comes to the low, especially pre-hypo range, I will trust my OTU over any other meter. Next to that meter, I would use the ACAdvantage. So many are worried about the amount of blood and yes, the ACA does take more, but the OTU...hey, you need to see a little blood for any meter and with all the comparing I did a few years back, the OTU doesn't take any more blood than the other meters.
 
That's very interesting, Hope. I switched from the OTU because the strips were so expensive. And also, the amount of blood was an issue for us. The Wavesense Presto has, for us, been much easier to use and the strips MUCH cheaper. But again, we all have only our single experiences with these meters and who knows? So many other things are variable, too. We learned to test with the OT, so we came to the Wavesense as more experienced testers.
 
I have both a OTU and a Maxima, ( and a Freestyle and a ...?) I really like the Maxima because everytime I need to retest because of a unexpected reading, the second reading is always very close to the first (not the case with some other meters), and it uses .5 drop. (and it has cheeeeeep strips so I can test a lot :-D ) It tests higher than the Freestyle, and lower than the OTU.

BTW the fructosamine number is not a direct comparison to a blood glucose test average. There is a rough conversion, and charts are available somewhere in cyberspace (actually there are several different conversion charts ive seen, soo....)
 
Thanks for the info Nancy! I've also had the Maxima test close when having to redo a test--and I do find the blood volume difference to be significant between the Maxima and the OTU. Considering the number of times I haven't had enough for the Maxima, it is pretty significant!
 
The OTU is actually a FastTake, just upgraded. In Consumers they tested meters and FastTake won out for consistency....back to back readings almost identical.
 
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