Glutamic Acid Decarboxylase Antibodies test is used to discover whether the patient has Type 1 Diabetes or Latent Autoimmune Diabetes of Adulthood. This test is favoured for which type of diabetes from C- peptide test which measures how much insulin is produced by the body. This test is particularly of use to the patients above the age of 30 and suffer from diabetes and type 2 diabetes is in doubt for example if the patient is not overweight. This test also determines whether diabetes within pregnancy known as gestational diabetes is type 1 diabetes or not.