The term 'blood sugar' is a misnomer since it means only glucose. Yet there are other sugars besides glucose that are present in blood. Food contains several different types of sugars e.g. fructose from fruits, galactose and lactose from milk and dairy, sorbitol, xylose, maltose etc. These sugars are inert with regard to the human metabolism and its regulation by insulin hormone and thus blood sugar tends to refer to glucose alone.