Who's on First? What's on Second? I don't know is on Third (confusing CGM numbers)

Liam’s CGM read 84 45 degrees downward, but Liam came to me and said, “Papa, my legs are shaking.” I say to myself (and to him)…maybe you’re feeling a low BG! Let’s go see? When I check him, here are the numbers I get…see if these numbers make sense to you.

So, when I did the first finger stick and drew a 242 (7:08p), naturally, my instinct is…well, I guess I should have cleaned off his finger because he did just have a Swiss Roll (1/2 of 1, actually…15 carbs). So, I select another finger, CLEAN IT this time with an alcohol wipe and wait 30 seconds or so, and do a second finger stick and this time I drew a 387! Now I’m like…wth? Scratching my head, I say…ok, maybe these are just bogus readings…2 of them, back to back. So I say, sorry Liam, we need to do a 3rd finger stick. So I go through the same process on a 3rd finger…clean it, wait, then stick him and at 7:10p, the number is more in line with what I was expecting, 118.

So, naturally, because we now had 3 very wildly different and confusing numbers (hence my Abbott and Costello reference in the subject line…if you’re not aware of it, it’s only the best skit ever in the history of mankind with the 2 best comedians of all time (can be found here), I had to take a 4th finger stick just to VERIFY one of the three vastly different readings and the 4th reading was 124.

Here are 3 of the 4 finger sticks (I didn’t get the last BG in the pic, but it was 124).

I don’t think I’ve ever had 3 or 4 wildly different BG’s before like this so I thought I’d post my experience. What a fun time!

The good news was that he did NOT have a low. Bad news is that he did NOT have a low recognition event…but he’s thinking about it and notifying me when his body feels different so who knows what was going on.


I suspect this may have impacted first 2 meter bgs. Maybe a hand washing in this case is better than alcohol swabs.
Alcohol pads may just swoosh the sugar residue around.


Alcohol pads work OK, but as @MM2 said they just move the sugar around according to my Endo. Most of the life scan meters I had used to say to wait until the alcohol was dry so it wouldn’t corrupt the reading. I assume this is also the case with better meters.

I personally get wonky numbers with alcohol pads. I hand wash (this includes last 2 hospitalizations) before testing.


Alcohol wipes usually solve it for us, but I guess it sounds like in this case they let me down! I’ll make sure to wash hands in the future when/if this happens again.


When I get a wonky number I always wash my hands well with soap and water before I test again. It’s amazing how the smallest amount of food residue will impact a fingerstick.


I just can’t believe it’s taken 3 years for us to run into this problem. lol. He is always holding food in his hand of some kind and it’s never interfered before.


I agree with everyone else about hand washing. With food allergies, we’re told that things like hand sanitizer and alcohol swabs don’t remove allergen proteins (and don’t “kill” them, either), they just smear them around. Only hand wipes (like Wet Ones) or hand washing will remove allergens. I’d think the same would apply to glucose, since it’s also from food residue. I keep a packet of Wet Ones around and use them before testing if I don’t have access to water (and also to wipe hands or surfaces down for allergens).


I would suggest the 90% alcohol found at Walmart. I used to use the 70% alcohol swabs, but only had marginal results. I have found that using different meters to test blood produced more consistent results. I use One-Touch meters as a final backup.

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He may have felt a steep drop, even if it wasn’t a low. Samson has been getting better lately about feeling lows and telling us. But hes has a lot of false alarms, where he confuses hunger, tiredness, or being high for being low.

Liam’ll get there!! And yes, we have had a few of these situations before. WE always make Samson wash his hands before testing because sugar has messed up a few of our readings. Bonus is that his he’s often gotten into something messy/dirty so he looks slightly less scruffy :slight_smile:


new here but had to comment. For years (mom was a t2 for over 40yrs) I’ve asked docs about the possibility if not food residue but other things like lotions to vehicle antifreeze could affect meter readings. Been universally told not a chance that we should wash our hands to reduce chance of infections. They indicated the way meters analyze blood ignored surface contaminants on skin. I was still skeptical.

I was Dx’d over a decade ago and never did more that an alcohol wipe. When i finally had to start using insulin a few years back i checked around online to help me avoid, well, putting. myself into a warm cozy coma. Info has been more toward soap & water but use a basic soap nothing full of additives. I seemed to note differences if i had to test multiple times.

The comments here seem to add more support to at least have washed my hands recently and not gotten anything on them. I say why not just so it when practical…it can’t hurt. Thanks!


Skeptical is good.
When people tell you things that sound cra-cra and then can’t explain it then my assumptions is they are just full of BS.


And anytime we get a fingerstick reading that makes us go Hmmm… before we test again, we wash and dry hands. Soap, water and towel. Nothing else and no alcohol wipe.

We do use alcohol wipes to prep the skin before Dexcom sensor and pump infusion set insertions. But not fingersticks. Actually don’t even bother with alcohol for syringes anymore. On the pump but sometimes a syringe seems appropriate.



You’re right! Hand washing is a healthy habit and one that makes for less sticks in the long run!

We had a chat about this in the past that you might find interesting:

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