Normal Values:

Up to 100 milligrams per deciliter (mg/dL) is considered normal for a fasting blood glucose test.

Persons with levels between 100 and 125 mg/dL have impaired fasting glucose, a type of prediabetes. These levels are considered risk factors for type 2 diabetes and its complications.

Diabetes is diagnosed in persons with fasting blood glucose levels that are 126 mg/dL or higher.

Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

What abnormal results mean:

Higher-than-normal blood glucose levels (hyperglycemia) may be a sign of diabetes. In someone with diabetes, it may mean the diabetes is not well controlled.

Increased levels may also be due to:

• Impaired fasting glucose (also called "prediabetes")
• Overactive thyroid gland
• Pancreatic cancer
• Pancreatitis
• Pheochromocytoma,acromegaly,Cushing syndrome, or glucagonoma (all of which are rare causes)

Lower-than-normal levels (hypoglycemia) may be due to:

• Hypopituitarism
• Underactive thyroid gland
• Insulinoma (very rare)
• Too little food
• Too much insulin or other diabetes medications