According to a new study published in Diabetes Care, your finger-prick blood glucose test may be “abnormally and significantly high” if you test after handling fruit without first scrubbing your hands thoroughly and vigorously.
The Tokyo study, precisely titled “Glucose Monitoring After Fruit Peeling: Pseudohyperglycemia When Neglecting Hand Washing Before Fingertip Blood Sampling,” tested ten non-diabetic volunteers who had normal blood glucose levels of approximately 90 mg/dL.
The volunteers were asked to peel an orange, a kiwi, or a grape. When they then tested their blood glucose without washing their hands, their blood glucose meter produced results of 170, 180, and 360 mg/dL respectively. Even after they swabbed their test finger with alcohol five times, the meter results were inaccurately high. It was only after a thorough handwashing with tap water that they got an accurate result from their meter.
The researchers concluded, “To avoid overestimation of blood glucose using portable monitors, the hands should be washed before monitoring capillary BG, especially after fruit has been handled.”