Because the blood glucose measured by a glucometer is fingertip blood, it will be slightly higher than the blood glucose measured by a venous blood draw. Blood travels from the arteries to the capillaries and then to the veins. The blood needed for blood glucose measurement by a glucometer is capillary whole blood, which contains red blood cells, white blood cells and other components. The blood needed for venous blood sampling to measure blood glucose is venous blood, with capillary blood in front, so the measured blood glucose value will be slightly higher. Since blood glucose measured by blood glucose meter is usually self-tested, if you find that the self-tested blood glucose value is high, you can go to the hospital in time to consult the doctor and draw venous blood to measure blood glucose.