The 3 main types of diabetes are: 1/ Type 1 diabetes, also known as juvenile-onset or insulin-dependent diabetes mellitus (IDDM), 2/ Type 2 diabetes, also known as adult-onset or noninsulin-dependent diabetes mellitus (NIDDM) and 3/ Gestational diabetes.

A glucose level over 200 mg/dL means that you have diabetes.

A blood test for glucose after you have fasted, called fasting plasma glucose (FPG) value. An FPG value of 126 mg/dL or greater means that you have diabetes.
If your blood glucose value is 140 mg/dL or greater, your doctor will most likely want more tests before diagnosing you. Oral glucose tolerance test (OGTT) is another option; 200 mg/dL or greater means that you have diabetes.

Treatment is focused on keeping blood sugar in the normal range.