Connect
← Return to What metric to watch?
Discussion
Comment receiving replies
I had heard that blood was more accurate than interstitial fluid too, which is why getting two wildly different blood results, in the space of a minute, confuses me. To be clear, it goes like this.
I wake up, my cgm says my blood sugar is 152, which is in the range I usually fall in the morning. I test and get 218 or 72, something that is very far from 152. I think "Wow, what is that about?" I immediately test again and get 148. I test a third time, and get 143. Meanwhile a few minutes later my cgm reads 150, and the curve stays steady till I eat an hour or two later, so it isn't an issue of my cgm lagging.
Replies to "@louiserivers I had heard that blood was more accurate than interstitial fluid too, which is why..."
@anonymom3 said:
>I wake up, my cgm says my blood sugar is 152, which is in the range I
>usually fall in the morning. I test and get 218 or 72, something that is
>very far from 152. I think "Wow, what is that about?" I immediately test
>again and get 148. I test a third time, and get 143. Meanwhile a few
>minutes later my cgm reads 150, and the curve stays steady till I eat
>an hour or two later, so it isn't an issue of my cgm lagging.
When you say "I test" you mean finger sticks?
I just asked Google and it says that the CGM generally tests much more often than it reports, so every reading it gives is already an average over several minutes.
If you are getting that much variation in finger sticks, I'd ask which meter are you using, and you might want to try another. My Contour Next meter is more accurate than my CVS meter, but as I said even the CVS is acceptable, but you might slightly discount any readings that are very high or very low, it exaggerates the distances from "normal".
I seldom retest within a couple of minutes and when I do I try to switch meters, how much variation one can really see in just a minute or two I don't know, and I guess even the CGM won't tell you either (unless it has a magic mode that is meant to do just that!). Wait, I'll go ask Google that, too.
Aha. First, Google points out that the CGM measures interstitial, and that changes more slowly than blood glucose tested by finger sticks. Second it says some CGMs might report shorter periods on the app but only stores 5 (or 15) minutes averages that it officially reports. Also it says that anomalous readings are more likely caused by contamination on your hand, or squeezing the finger too hard and diluting the blood with interstitial fluid.
Do you wash hands or use a little alcohol wipe pad to clean the finger, and also let the alcohol evaporate back off? When they gave me the meter kit they didn't give me the wipes until I asked!
HTH
Connect
@anonymom3 Some cheap meters are not very accurate. You also have to make sure your fingers are clean with no residual soap/alcohol/water residue, so the small sample is not contaminated. At 150 the fasting glucose level is about a 7 A1c. Average glucose will be higher with 210 equal to a 9 A1c. The average needs to be over 300 to get a 13 A1c.