MODEL RELEASED. Diabetes clinic, blood sugar test. Hands of a nurse using a testing device on blood from the finger of a diabetic patient. The device measures the levels of the sugar glucose, here 9.9 millimoles per litre (this is a post-breakfast reading). An insulin injection will be needed to lower the levels to the normal range of 4-6 millimoles per litre. This is the BGStar blood glucose monitoring system from Sanofi. Diabetes mellitus affects glucose sugar metabolism. Blood sugar is not oxidised due to a lack of the pancreatic hormone insulin. Treatment is based on a strict diet and insulin injections to maintain the blood-sugar balance.