Meter variance

[chuckstables]

Hi guys,

So i tried to test sam, had to poke multiple times to get enough blood. First time i barely got enough, and it said 16.5 so 297. I tried again, had to poke twice and it was 10.2…..

Is it only accurate if you poke once and get more than enough blood? Annoyed that I just wasted a couple test strips lol. Going to try to retest on my last break

 

[chuckstables]

Well turns out that he's just bouncing. Ugh. Hopefully it ends soon lol.

 

[Sienne and Gabby (GA)]

My philosophy is that if a test result doesn't make sense, get another test. And if the two tests are at odds with one another, test again. (I had a pretty compliant cat!) Also, you need to be doing the tests in rapid succession so you're pretty certain that there's not a change in numbers.

Allowable meter variance is about 20%. However, you can always have a bad strip, a bad test, or get a wonky number for no apparent cause other than the moon is in a weird phase!

 

[chuckstables]

My philosophy is that if a test result doesn't make sense, get another test. And if the two tests are at odds with one another, test again. (I had a pretty compliant cat!) Also, you need to be doing the tests in rapid succession so you're pretty certain that there's not a change in numbers.

Allowable meter variance is about 20%. However, you can always have a bad strip, a bad test, or get a wonky number for no apparent cause other than the moon is in a weird phase!

The first super high one I barely got enough blood, the contact strip that turns red when u have enough only filled up about 40% of the way, so thats likely why.

Plus my meter is not as accurate at higher levels from what i read; my meter says it’s pretty much spot on below 6 mmols but far less accurate above 6.

 

[Sienne and Gabby (GA)]

For a meter to not be correct above 6 mmol (108 for those of us who are metrically challenged) is a bit worrisome. Obviously, a meter that's misreading if numbers are low is worse.

 

[chuckstables]

For a meter to not be correct above 6 mmol (108 for those of us who are metrically challenged) is a bit worrisome. Obviously, a meter that's misreading if numbers are low is worse.

it’s just that they constrain it below 6 to within 5%, and above it can vary the full 20? I think thats what it is anyway I’ll have to double check the manual, but they did like 2k tests on a a sample below 6 and then only like 100 above 6 lol. Weird. Its the bravo meter. Dirt cheap, strips

The real issue is that it barely had enough blood. The next reading had enough and it was consistent with the one i did an hr later. Sams ears aren’t bleeding as easily now.

 

[chuckstables]

So I was totally wrong about those numbers! Great example as to why eyewitness testimony is unreliable; because our brains corrupt memories every time we remember them.

So they ONLY did 114 tests in total to validate the meter. They used a commercial exact blood glucose analyzer, compared it with the results THEY got.

They found the following: The line of best fit is: True blood sugar = 0.97*Bravo meter blood sugar - 0.13, in units of mmols/l. Unlikely based on the sample size that the slope deviates from 1.00 to a statistically significant level. Similarily it's unlikely that the Y-intercept deviates from 0 to a significant level. I actually did the math; they're both consistent with a true formula of True blood sugar = Bravo meter blood sugar with a 95% confidence level.

So that's kind of interesting. Correlation coefficient is 0.993, so 98.6% of the VARIANCE (statistical variance) in TRUE blood sugar is accounted for by the measured blood sugar (you square the correlation coefficient to get the variance percentage explained).

Now here's the more interesting part: Below 4.2 mmols/l they only did 8 tests. Out of those all 8 tests were within + or - 0.28 mmols/l.

Above 4.2 mmols/l they did 102 tests. Out of those 49/106 (46%) were within 5% of the true blood sugar. 82/106 (77%) were within 10% of the true blood sugar. 101/106 were within 15% of the true blood sugar, and 106/106 were within 20% of the true blood sugar.