Diabetes is defined as a disease in which the body has a weakened ability to either produce hormonal insulin or react to it. In people with type 1 diabetes, the pancreas does not produce insulin. People with type 2 diabetes mellitus have cells in their bodies that are insulin resistant or have a pancreas that slows down or stops the production of adequate levels of insulin (blood glucose). Both types of diabetes mellitus can lead to abnormal glucose levels, says Dr. Slinkin.
Normal blood levels can vary slightly depending on which blood tests are used, and your doctor may have, but the variations are small. Except that the "normal" ranges for non-diabetics aren't the same for diabetics; it's generally accepted that the target blood sugar measurements for people with diabetes will be slightly higher than those without diabetes, Denis says.
A person who does not have the normal glucose range of 72-99 mg/dL at fasting and up to 140 mg/dL for about 2 hours after a meal. People with diabetes who have well-controlled glucose levels with medication have a different target glucose range. These people may have a fasting range of about 100 mg/dL or less and 180 mg/dL about 2 hours after a meal. If a person has poorly controlled diabetes, he or she may have a much higher glucose range or hypoglycemia (e.g. 200-400 mg/d; however, some people with diabetes have much higher blood sugar levels FBS.