Type 1 Diagnosis

Because the onset of type 1 diabetes is usually fast and severe, diagnosis is often made in a hospital or emergency room. However, the blood tests for diabetes diagnosis can also be given in a doctor's office or lab.

These tests, and the values for diabetes diagnosis, are as follows:

• An A1C value of 6.5% or more.
• A random plasma glucose value of 200 mg/dl (11.1 mmol/l) or more (in the presence of diabetes symptoms).
• A fasting plasma glucose value of 126 mg/dl (7 mmol/l) or more.
• An oral glucose plasma glucose value of 200 mg/dl (11.1 mmol/l) or higher at 2 hours post-glucose load.

If your blood sugar is not significantly elevated, a second follow-up test may be ordered to confirm the diagnosis. In addition, your doctor may also prescribe additional blood tests to differentiate between a type 1 and type 2 diabetes diagnosis. These include a c-peptide test (which measures levels of this protein associated with insulin production) or tests for islet cell antibodies (ICA), insulin auto-antibodies (IAA), and/or glutamic acid decarboxylase (GAD).