Oral Glucose Tolerance Test
You have prediabetes if the results of your oral glucose tolerance test are 140 to 199 mg/dL (2 hours after the beginning of the test).
High glucose levels may be caused
Low glucose levels may be caused
- Certain medicines, such as medicines used to
treat diabetes, some blood pressure medicines (such as propranolol), and some
medicines for depression (such as isocarboxazid).
- Decreased production of
the hormones cortisol and aldosterone (Addison's disease).
- Problems with the thyroid gland (hypothyroidism) or an underactive
- A tumor or other problems of the pancreas.
- Liver disease.
Many conditions can change blood glucose levels. Your
doctor will discuss any significant abnormal results with you in
relation to your symptoms and past health.
What Affects the Test
Reasons you may not be able to
have the test or why the results may not be helpful include:
- Taking certain medicines, such as
corticosteroids, diuretics, seizure medicines, birth control pills,
nonsteroidal anti-inflammatory drugs (NSAIDs), and some medicines used to treat
high blood pressure.
- Recent surgery, illnesses, and infectious diseases.
- Weight loss through dieting.
- Long periods of bed rest (such as from a hospitalization or illness).
What To Think About
If you are diagnosed with gestational diabetes, you have a higher risk of developing diabetes later in life. The American Diabetes Association recommends screening for diabetes and prediabetes every 3 years.2
American Diabetes Association (2012). Diagnosis and classification of diabetes mellitus. Diabetes Care, 35(Suppl 1): S64–S71.
American Diabetes Association (2013). Standards of medical care in diabetes—2013. Diabetes Care, 36(Suppl 1): S11–S66.
Other Works Consulted
Chernecky CC, Berger BJ (2013). Laboratory Tests and Diagnostic Procedures, 6th ed. St. Louis: Saunders.
Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.
Primary Medical Reviewer
||E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer
||Alan C. Dalkin, MD - Endocrinology
||July 5, 2011