Random blood sugar; Blood sugar level; Fasting blood sugar

Levels vary according to the laboratory, but in general up to 100 milligrams per deciliter (mg/dL) are considered normal for a fasting blood glucose test.

Persons with levels between 100 and 125 mg/dL have impaired fasting glucose, or prediabetes. These levels are considered to be 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.

Greater-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:

• Acromegaly (very rare)
• Cushing syndrome (rare)
• Glucagonoma
• Impaired fasting glucose (also called "prediabetes")
• Hyperthyroidism
• Pancreatic cancer
• Pancreatitis
• Pheochromocytoma (very rare)

Lower-than-normal levels (hypoglycemia) may indicate:

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

Images

Previous Section

Glucose test Overview

Next Section

Glucose test Risks

Review Date: 05/23/2010
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)