Go Wash Those Hands!

by Leighann on February 16, 2011

Every single time a number in the 300’s pops up on our blood glucose meter, I instruct Q to go wash her hands again and we do another test.


Because one time when Q was low I gave her some Skittles. Fifteen minutes later she was in the 300’s! I thought that surely a 10 gram carb serving of Skittles wouldn’t shoot her up more than 200 points! After a hand wash and another BG check, we realized she was nicely in range. That sugar on her finger caused a false high reading. Could you imagine if I gave a correction based on that high number?

Now each time the school calls with a high reading my first question is: Did you have her wash her hands and check her again?

When I mentioned that we only go through a box or two of alcohol swabs a year since switching to an insulin pump (read about the alcohol swab recall), I had several parents ask why we don’t wipe Q’s finger with an alcohol swab before a BG check.

We did this in the beginning, but quite quickly the CDE told us to switch to good old soap and water. Alcohol dries the fingertips and can make finger pricking more painful.

A recent study published in the American Diabetes Association’s Diabetes Care journal verifies that not only can you get false high readings from sugary residues on fingers, but also that soap and water is best.

Though I have to wonder how many hundreds of thousands, if not millions, of dollars were spent to find this out!

Here is the abstract:

Glucose Monitoring After Fruit Peeling: Pseudohyperglycemia When Neglecting Hand Washing Before Fingertip Blood Sampling

OBJECTIVE To examine whether hand contamination with fruit results in a false blood glucose (BG) reading using capillary fingertip blood sample.

RESEARCH DESIGN AND METHODS The study subjects were healthy volunteers with normal glucose tolerance test. Capillary BG samples were collected from the fingertip after peeling orange, grape, or kiwi fruit, followed by no action, washing hands with tap water, or rubbing the fingertip with an alcohol swab, then analyzed with glucose monitors.

RESULTS The BG levels measured after peeling any of the fruits, followed by washing hands, were similar to the control subjects (no fruit handling), but the levels after fruit peeling, followed by no washing, were abnormally and significantly high, even when the fingertip was cleaned once or five times with an alcohol swab before blood sampling.

CONCLUSIONS To avoid overestimation of blood glucose using portable monitors, the hands should be washed before monitoring capillary BG, especially after fruit has been handled.

{ 10 comments… read them below or add one }

1 Bob P February 16, 2011 at 6:37 am

The other day, after a brief moment of panic, I washed about 240 points off my hands….


2 Lani February 16, 2011 at 8:36 am

We almost gave a correction for a high before hand washing also. Taylar had eaten a pear. and after washing she was only 70!


3 Linda February 16, 2011 at 9:00 am

since we got false highs many times way back in the beginning, J always washes his hands before testing now. not only does it ensure a correct number, but washing your hands ten times a day keeps the germs away too! J is hardly ever sick & i’m quite sure it’s because he washes his hands so much! diabetes bonus! =)


4 Scott February 16, 2011 at 9:13 am

CGMs are quite handy in these situations, though nothing beats a hand washing. Great post!


5 tmana February 16, 2011 at 9:47 am

I noticed this very early in my tenure with diabetes. The worst culprits, IMO, have been balsamic vinegar and citrus oils — both of which are very stubborn even in the face of soap and water.


6 Carol February 16, 2011 at 11:06 am

We learned this too- just have to keep remembering! First instance, fingers COVERED with markers (in the first place, why was it ok to think this was ok?!?), “Who knew~ A blood sugar on hands washed vs covered with marker would lower a blood sugar by 25 points. So due to technical difficulties, we now have a 66. :)” and now highs during the nights. Sunday night I got back out of bed to wash and recheck to confirm the high, Yes it really was almost 300. :/


7 Amy Scheer February 19, 2011 at 1:43 pm

What about washed and STILL covered with marker? Seriously–I’m askin’.


8 Allison Blass February 16, 2011 at 11:52 am

I’ve definitely had this happen, but not too often. Usually I just do it if it’s an unexpected high blood sugar. If I did it for every single one, I’d go through too many strips!


9 Angela (Toucan Scraps) February 17, 2011 at 11:41 am

we carry a small spray bottle wcontaining tap water and some cotton wool pad around in our kits for cleaning fingers when out and about. As they are in the same place as the meters we can also resort to using them in emergencies in the house.
TJ gets reward tokens, and occasionally can loose them – one call for loosing a token is not washing her hands before a blood test – wastes test strips and risks getting too much correction dose of insulin.


10 Julie April 26, 2013 at 9:16 am

My DD was just dx 3/10/13. My husband has diabetes too, for the last 14 years. He washes his hands, but I’ve been using the alcohol swabs on her, because I can bring everything to her to test her and not have to get up, get the stool so she can reach the sink… find a towel to dry off, and on and on. We can yes in a restaurant w/o having to go into the restroom. It’s just more convenient.

However we did get a crazy high number last night. She was low, at 70, and she ate one of these new “Quick Sticks.” We got free samples, and she wanted to try them. (She liked them! They are sort of like a big Pixie Stix) When I tested her 15 minutes later it was 217! I knew it was wrong, because I’d just seen the 70. We re-checked and got a more reasonable number.

Later, I checked her at 3:00 am and she was at 315. After reading your post, now I’m wondering if she had that powder on her hands even then! (I did use alcohol swabs each time)


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