Glucose test

Alternative names:

blood sugar levels; fasting blood sugar; FBS

Normal values:

64 to 128 mg/dl

Note: mg/dl = milligrams per deciliter

What abnormal results mean:

Greater-than-normal levels (hyperglycemia) may indicate:

• acromegaly (very rare)
• Cushing's syndrome (rare)
• diabetes mellitus
• 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 the 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
• insulin-dependent diabetes mellitus (IDDM)
• islet of Langerhans' tumor
• multiple endocrine neoplasia (MEN) I
• noninsulin-dependent diabetes mellitus (NIDDM)
• pituitary Cushing's (Cushing's disease)
• syphilis
• syphilis, primary
• syphilis; secondary
• syphilis, tertiary
• transient ischemic attack (TIA)