Fingerstick and Handwashing

The Dexcom G5 wanted a calibration and it was going into nighttime as well as the cgm data showed straight and level so it seemed a good time to calibrate.

Using our Contour Next One we did a fingerstick as normal. The resulting number on the meter seemed surprisingly high. Not crazy high but enough that it made us do a double take. As well, the calibrations are usually very close between the meter and the cgm but this was off by quite a bit. On the other hand, this cgm graph was showing a little shaky today and it is on day #10 where we usually only get 12~13 days so maybe it was just going to end early.

Given it is right before bed, we decided to play it safe, wash hands and recheck on the meter.

The number came up 26 points lower after washing hands which also put it within 10 points of the cgm. We realized that the nighttime supplements/vitamins had just been handled so our reasonable assumption is at least one of those pills likely has a bit of a sugary coating and impacted the meter reading.

So total newbie question - do you not wash hands before every fingerstick? I do know a lot of people don’t; curious how often something like this happens? I hate wasting test strips, so I wash my hands to make sure I don’t have to use more than one. :blush: Heading into wintertime, though…my skin is already cracking.

Probably a good call on it being from the supplements. Ha, made me think of my daughter’s vitamin gummies. I haven’t looked at the sugar content because I don’t even want to know…

I can safely say, nope. On a tough day we might stick 10 times. Many of those will be away from home, and many away from a building. You go for clean as you can get, and give it a whirl.

1 Like

EH doesn’t wash hands every time either. Although, tonight, after the flattest line he’s had (around 106 for 12+ hours, which is the best he’s had in months) the stupid Dex was wrong by, like, 40 points when he did an unwashed-hands-fingerstick. So I made him get up and wash his hands and do a test on the Freestyle meter. He commented that it was a waste of hand washing. Sure enough, it was the exact same number on the Freestyle twice.

If you think about it, you probably wash your hands a lot during the day. If you use the bathroom, change your baby, cook food and get your hands sticky, etc. you’re probably washing up after that. So…maybe ever time isn’t necessary?

I have severe eczema on my hands and have been told to only wash my hands after using the washroom and before eating or preparing food. So I carry unscented, hypoallergenic, as un-chemicalled as possible wet wipes (and this winter will try making my own so that I can control exactly what’s in it and avoid chemicals that may irritate my eczema) that I can use to clean my hands in between washing. I’ll often use them if I want to test or eat food while away from a building and have been touching shared surfaces like handrails on buses and the like. I think it probably also helps me to not get sick. :slight_smile:

1 Like

Back with baby #1 when we seriously had no money, we made our own baby wipes. As I recall, they were extremely effective.

Oh, wipes, good idea. I always have those around LOL I generally have trace amounts of food on my hands because my daughter is a constant snacker (trouble with coming from two families with major metabolic needs!), so I feel like that would throw off results if I didn’t at least wipe my hands off.

As a general rule, washing your hands is best, but life gets in the way, so you may not always be able to. But in reality, there are only some types of foods on your fingers that will mess it up. Dry foods are not too bad. Sticky sugary things, sweet drinks, or oily things will mess it up for sure.

There are 2 fingers I use for normal everyday testing. What I have learned is to just not touch any food with those 2 fingers. That helps.


I do, almost every time, but that’s because it’s fairly easy for me. I work at home, so the PDM and a sink are always close to each other. If I’m eating out, I might dip my finger in my water glass. If there’s no reasonable option to clean, then I use a part of my finger that is less likely to have been in contact with surfaces. At the best of times there can be at least a 1 mmol disparity between the fingerstick test and the CGM, so I want things to be as accurate as possible.

Even if I have just washed my hands, part of me wonders if the PDM itself hasn’t been contaminated, or the strip container, or even the lancet. After all, they’re usually being handled while food prep is under way.

You may call me Howard Hughes. I am strong.


I’ll have to start kneading dough my pinkies up. A startling image.


Yep, for food prep and stuff it doesn’t work. But for things like snacking on chips I keep those two test fingers away… :smile:


Oh, that might work. I usually alternate hands each day (my fingers get bruised easily, so I have to be careful not to over-test on any of them), so might just start making sure I get my daughters snacks one handed…I do almost everything with one hand anyway at one point or another, holding baby. :laughing:


I actually wear gloves for most of my food prep, otherwise my hands get crazy itchy and eczema flares up. But I also tend not to often touch stuff with my pinkies in the course of daily life, so they’re my go-to if I have to test and can’t clean my hands first.

1 Like