Glucose Monitoring After Fruit Peeling: Pseudohyperglycemia When Neglecting Hand Washing Before Fingertip Blood Sampling: Wash your hands with tap water before you check blood glucose level

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.