The random sugar level test can be used to measure the blood glucose level at any time. Blood glucose levels of between 140 mg/dl and 200 mg/dl may signal the onset of diabetes. This condition is known as pre-diabetic.However, the normal blood glucose level should never exceed 200 mg/dl. 1  Oral glucose tolerance test.ormal Random Blood Sugar Levels. Normal random blood sugar levels fall within a standard range of between 70mg/dl to 150mg/dl. This variation can be attributed to various factors including the time, type and volume of food consumed during previous meals.