Wet or Unwashed Fingertips
The most common glucometer error costs nothing to fix and almost nobody fixes it. If you've handled fruit, rinsed your hands without drying them fully, or applied hand cream before testing, the residue on your skin mixes with the blood sample. Glucose from mango juice or banana pulp on your fingertip will read as your blood glucose. A 2019 study published in the Journal of Diabetes Science and Technology found that 26% of home glucometer readings deviated by more than 15% from laboratory reference values, and contaminated fingertips were among the leading causes. Wash hands with plain soap, dry them completely, then prick. The first drop of blood often carries interstitial fluid from the puncture itself; wipe it away and use the second drop for a cleaner sample.
