How Diabetes Is Diagnosed

If you have any of the common symptoms that suggest the presence of diabetes, your doctor will order laboratory tests to confirm the diagnosis. Regular screening tests to measure blood glucose levels are recommended for certain people who have no symptoms of diabetes.

To promote the early detection of diabetes and reduce the risk of long-term diabetes complications, the American Diabetes Association recommends that individuals age 45 and older be screened for the disease every three years. Screening is also recommended for individuals under age 45 who have an increased risk of diabetes because of obesity, high blood pressure (140/90 mm Hg or higher), or ethnicity (black, Hispanic, Asian, or Native American).

Other examples of risk factors that merit early or more frequent screening (for example, every one to two years) include a history of diabetes in a first-degree relative (a parent or sibling), diagnosis of diabetes during pregnancy (called gestational diabetes), delivery of a baby weighing more than 9 lbs, low levels of HDL cholesterol (less than 40 mg/dL), high triglyceride levels (150 mg/dL or higher), or prediabetes. If screening tests show that you have diabetes, your physician will perform regular laboratory tests and physical examinations to monitor the progression of the disease.

Medical History and Physical Examination

If you are diagnosed with prediabetes or diabetes, your doctor will pay extra attention to factors in your medical history and physical examination that could affect your diabetes care.

In taking your medical history, the doctor will ask about the date and circumstances of your diabetes diagnosis, your dietary and exercise habits, your weight history, any medications you are taking, your alcohol and tobacco use, and your family history of diabetes, heart disease, and stroke. If you use oral diabetes drugs or insulin, the doctor will record when you take these medications and how much, the effectiveness of blood glucose control (based on symptoms of high blood glucose and blood glucose values), the frequency and timing of symptoms of hypoglycemia (low blood glucose) or ketoacidosis, and any symptoms of long-term diabetes complications.

Your physical examination should include measurements of your weight and blood pressure and a foot inspection to look for common diabetes-related problems such as ulcers and other skin abnormalities, joint problems, and loss of sensation. Because diabetes can affect your vision, you should have a dilated eye examination performed by an ophthalmologist (a medical doctor who specializes in diseases of the eye).

Publication Review By: Written by: Christopher D. Saudek, M.D.; Simeon Margolis, M.D., Ph.D.

Published: 20 Apr 2009

Last Modified: 11 Sep 2015