Venous blood glucose is generally higher than fingertip blood. Fingertip blood glucose actually detects blood glucose in the capillaries, while blood glucose measured in the veins is blood glucose in the plasma. Fasting fingertip blood glucose is generally lower than venous blood glucose because fingertip blood glucose is whole blood from the capillaries, while venous blood glucose is measured by separating red blood cells and using plasma. To ensure the accuracy and reliability of the test results, continue with your usual diet and habits and get a good night’s sleep the day before the test. Also avoid strenuous exercise, smoking and drinking stimulating beverages such as coffee before the blood test the next morning. If the blood glucose test exceeds the standard in a more serious situation, it is recommended to consult a doctor for retesting in time, so as not to delay the condition.