Levels up to 100 mg/dL are considered normal.

Levels between 100 and 126 mg/dl are referred to as impaired fasting glucose or pre-diabetes. These levels are considered to be risk factors for type 2 diabetes and its complications.

Diabetes is typically diagnosed when fasting blood glucose levels are 126 mg/dl or higher.

Note: mg/dL = milligrams per deciliter

Greater than normal levels (hyperglycemia) may indicate:

• Acromegaly (very rare)
• Cushing's syndrome (rare)
• Diabetes mellitus -- fasting blood glucose of greater than 126 mg/dL
• Impaired fasting glucose -- 110 to 126 mg/dL -- a prediabetic state
• Hyperthyroidism
• Pancreatic cancer
• Pancreatitis
• Pheochromocytoma (very rare)
• Insufficient amount of insulin
• Excessive food intake

Lower than normal levels (hypoglycemia) may indicate:

• Hypopituitarism
• Hypothyroidism
• Insulinoma (very rare)
• Injection of too much insulin
• Insufficient dietary intake

Additional conditions under which this test may be performed:

• Acute adrenal crisis
• Cushing's syndrome caused by adrenal tumor
• Cushing's syndrome - exogenous
• Delirium
• Dementia
• Dementia due to metabolic causes
• Diabetic hyperglycemic hyperosmolar coma
• Diabetic ketoacidosis
• Diabetic nephropathy/sclerosis
• Ectopic Cushing's syndrome
• Epilepsy
• Generalized tonic-clonic seizure
• Glucagonoma
• Islet of Langerhans' tumor
• Multiple endocrine neoplasia (MEN) I
• Pituitary Cushing's (Cushing's disease)
• Syphilis
• Syphilis - primary
• Syphilis - secondary
• Syphilis - tertiary
• Type 1 diabetes
• Type 2 diabetes
• Transient ischemic attack (TIA)