Fingertip blood glucose does not always add 20%. A patient’s fingertip blood and venous blood measurements are about the same in the fasting state, but after a meal the fingertip blood measurements are slightly higher than the venous blood. Fingertip blood contains both arterial and venous blood. When a diabetic patient is fasting, the values of arterial and venous blood are basically equal. If the patient has a meal, the measurement will be slightly higher than venous blood because the fingertip blood contains some arterial blood. In general, a ten percent difference between fingertip and venous blood is considered reasonable. In order to minimize errors and ensure more accurate fingertip blood glucose, care should be taken to ensure that the glucose meter batteries are sufficiently charged, the test strips are stored correctly, and the fingers are dry during the test. If blood glucose abnormalities occur, it is recommended to seek medical attention promptly.