Many people think that fasting blood glucose of finger-end blood measured with a portable blood glucose meter is not diabetes as long as it does not exceed 7 (all units below are mmol/L), but this is actually wrong because it confuses capillary blood and plasma. Finger-end blood measures capillary blood with red blood cells inside, and by 7 we mean the blood glucose value of plasma after centrifugation of venous blood. Because red blood cells contain less glucose than plasma, and because inter-tissue fluid is added when squeezing finger-end blood, the blood glucose value of finger-end blood should be lower than the plasma blood glucose value during fasting. So the standard for finger-end blood is 6.1, not 7. If your finger-end blood is over 5.6, you should monitor your blood glucose, and if it is over 6.1, then you should check your venous plasma glucose to determine if you have diabetes. Of course the standard for postprandial finger-end blood and plasma blood are the same, such as no more than 7.8 2 hours after meal and no more than 11.1 for immediate blood glucose. the most accurate blood glucose measurement is plasma blood.