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Blood Sugar Readings – By Kelly Dawes

This does NOT include your CGM readings, these are for finger tests.

What Affects Your Blood Sugar Test Readings? You Will Be Surprised!

Since your doctor told you that you have diabetes, you’ve had to make a few changes. Among other things, you probably now must check your blood sugars using a meter.

Monitoring your glucose levels allows you to see the impact of the measures you are taking to better control your diabetes. Proper readings are crucial.

The test strips used with your meter are essentially mini labs on a piece of plastic. Many decisions are based on that lab result. Consider what might get into that small blood sample.

If you have sugar, food, even scented lotion on your fingers, your readings can be off. It is important not to skip the step of cleaning fingers prior to testing.

Here are some tips for successful blood sugar monitoring:

  • Wash your hands. Make sure finger is thoroughly dry before testing.
  • If unable to wash, use an alcohol prep pad. Wipe numerous times. Be sure that alcohol has completely dried prior to testing. Residual alcohol and even hand sanitizer can affect results.
  • Check expiration dates. Your test strips are labelled with an expiration date.
  • Storage matters. Test strips are sensitive to extreme heat and cold. The meter is as well. The test strips are sensitive to humidity, making bathrooms a less than desirable storage place.
  • Do not leave meter and strips in car during extreme weather conditions. The meter may not work when exposed to intense heat for an extended period. When I was younger and living in Arizona, I foolishly left my meter in my car on a summer day. The meter would not turn on for a few hours!
  • Insert a fresh lancet each time you test. Lancets that are used more than once are not as sharp as a new lancet. A dull lancet causes more pain and damage to skin.
  • Alternate fingers. Use the side of finger, versus the center of the pad, which is more painful. If you have difficulty getting enough blood from fingertip, try rinsing your fingers with warm water first. Or try shaking the hand below the waist or squeezing (“milking”) the fingertip.


Orange you glad you washed your hands?

Fruit, in particular, affects blood sugar results. A study was published in the Journal of Diabetes Care with 10 volunteers, none having diabetes. Their blood sugars were checked, with results generally around 90 mg/dl. The volunteers then peeled oranges, kiwis or grapes. Their blood sugars were checked again, after swabbing with alcohol. They peeled fruit once again and blood sugars were checked after washing hands in tap water.

The results: When the volunteer’s hands were washed with tap water, blood glucose readings matched the readings they had prior to peeling the fruit. However, when their blood sugars were measured after swabbing with alcohol, even up to 5 times, their readings shot up. 170 mg/dl for orange-peeling, 180 mg/dl for kiwi, and 360 mg/dl for the grapes.

The authors of this study say that the obvious message is to wash your hands with tap water, instead of relying on alcohol swabs before testing, especially when handling fruit.

To read more of this study, go to:

Stay Proactive

Needless to say, it is important to have clean fingers before checking blood sugar. We can’t assume that the results are a true reflection of the amount of sugar in the blood versus what residue was left on the fingertip. Also, tap water-washing may be the best way to ensure a truer blood sugar reading. Do your own research, see what you come up with. More importantly, keep monitoring your blood glucose levels and be proactive in the management of your condition. Remember, diabetes is a disease that can be managed when taken seriously. Only you have the power to ensure your story of diabetes has a happy ending!


Kelly Dawes has lived with T1D for 39 years. A Health Fitness Specialist, Consultant, Diabetic Educator who manufactures home fitness products.

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