The Mayo Clinic explains that the normal fasting blood sugar level range for a healthy adult is 70 to 100 milligrams per deciliter of blood. The American Diabetes Association recommends fasting sugar levels of 70 to 130, and no more than 180 after meals.
Patients who don't present low blood sugar level symptoms may need to keep higher glucose levels than normal. A health care provider personalizes and monitors blood sugar level care, and sets targets for specific medical conditions. Keeping glucose levels within a safe range prevents diabetic complications, and when in doubt, the patient should always consult a health care provider.