Diabetes is first diagnosed by symptoms. Urine tests and blood tests are then used to confirm a diagnosis. Symptoms can develop suddenly in healthy children or adults, and gradually over several years in overweight adults. If you have any of the following symptoms you should see your doctor for testing:

• Increased thirst
• Unusually frequent hunger
• Frequent urination
• Unusual fatigue
• Infections
• Blurred vision
• Cramps or burning sensation in your feet and/or legs
• Unexplained weight loss
• Nausea or vomiting
• Sores that do not heal

A fasting plasma glucose test (FPGT) is the preferred glucose test for diagnosing diabetes. You should see your doctor for a blood-glucose test at least once every three years.

Pre-diabetes, also called glucose intolerance, is a condition in which a person's blood glucose levels are higher than normal but not high enough for diagnosis of Type 2 diabetes. It is estimated that at least 20.1 million Americans have pre-diabetes. Left unmanaged, pre-diabetes can develop into Type 2 diabetes in 5-10 years. Lifestyle improvement, including better diet and more exercise, can prevent pre-diabetes from turning into this more serious condition.

For every person who has been diagnosed with diabetes, there is also someone who has it but remains undiagnosed - that's at least 18 million undiagnosed cases.

This is because many of the symptoms can initially be very mild or ignored. It is also possible to have very high blood-glucose levels, with damage to the body occurring, yet not feel unwell. This is called silent diabetes. It is still important to treat these cases, though, because research has shown that good control of blood glucose levels prevents or lessens the likelihood of the complications of diabetes. Therefore, you should have your blood-glucose level checked by your doctor every three years.