As
@Daibell mentioned, a c-peptide test is probably the most useful next investigation. C peptide is an indicator of your body's current insulin production - a low value suggests beta cells burning out and is considered typical of T1 (or severe later stage T2), while a high value suggests insulin resistance and is more characteristic of T2. If you are not currently taking insulin, another possibility is to order a glucose tolerance test (GTT) but make sure that insulin levels are measured, not just blood glucose levels. Do you know what your BG levels were when you were diagnosed with DKA and was it treated by additional insulin, or just hydration? Have you had a HbA1c test yet?