However, urine testing is not completely accurate because the reading reflects the level of blood glucose a few hours earlier. In addition, not everyone's kidneys are the same. Even when the amount of glucose in two people's urine is the same, their sugar levels may be different. Certain drugs and vitamin C also can affect the accuracy of urine tests. It's more accurate to measure blood glucose directly.
Kits are available that allow people with diabetes to test their blood glucose at home.
The test involves pricking a finger to draw a drop of blood. A doctor may suggest that someone test his or her blood glucose several times a day. Self-blood glucose monitoring can show how the body responds to meals, exercise, stress, and diabetes treatment. It measures the glucose that has become attached to hemoglobin, the molecule in red blood cells that gives blood its red color. Over time, hemoglobin absorbs glucose, according to its concentration in blood.