How to wash your hands before testing your blood sugar

If you have diabetes and your blood sugar tests are unusually high, here is something you should consider: Did you handle fruit just before your test? If so, invisible bits of fruit sugar on your hands may have made your blood sugar level look higher than it really is. This is due to the fact that fruit sugar sticks to the skin. How can you remedy this? Very simply – with a thorough hand washing with soap and water!

Blood sugar meters measure blood glucose (blood sugar) by taking a drop of blood from the tip of the finger and testing the sample on a reactive strip. Many diabetics have to measure their blood glucose several times a day to determine how much insulin to inject.

As part of a small study, Japanese doctors recruited ten healthy volunteers who did not have diabetes. The researchers measured the participants’ blood sugar levels in various conditions: First, the participants’ blood was tested after they had swabbed the tested fingertip with alcohol. Next, the volunteers peeled fruit with their hands and their blood sugar was tested without hand washing, then after swabbing with alcohol, and lastly after washing with tap water.

The result? When the participants washed their hands with water, their blood sugar readings were the same as before they had peeled the fruit. When they peeled fruit and took a blood sugar reading without washing their hands, their levels were often twice as high, due to residual sugar on their skin. And when they peeled fruit and then swabbed their finger with alcohol before testing, the readings were still higher than normal. In fact, even swabbing five times with alcohol didn't produce correct results.

The implications of this small study are clear: having residual fruit sugar on your fingers can artificially elevate blood glucose readings, and alcohol swabs are not the best way to clean your hands before performing the test. A thorough hand washing with soap and water is always best. Questions? Consult your pharmacist!