is this a diagnosis of type 1 or type 2 diabetes

Last edited 06/2020 and last reviewed 09/2020

differentiating between type 1 and type 2 diabetes

Clinical and biochemical clues to differentiate type 1 from type 2 diabetes

Factors favouring (but not indicative of) type 1 diabetes (1):

  • rapid onset of osmotic symptoms

  • normal or low body weight or rapid weight loss

  • ketonaemia >=3mmol/l on capillary testing or ketonuria

  • family or personal history of other autoimmnune conditions

  • failure to respond to oral therapy

  • positive antibody test (anti-GAD, insulin autoantibodies (IAA) and islet cell antibodies (ICA) most commonly used)

  • urine C-peptide:creatinine ratio less than 0.5nmol/l

The presence of one or more of these clues may point to a diagnosis of type 1 diabetes but absence does not exclude it (1).

A schemata for helping to to distinguish Type 1 from Type 2 diabetes has been detailed (2):