THE LABORATORY AND DIABETES RDG LESLIE, ERNESTO LOPEZ, STEPHANIE CUNNINGHAM INSTITUTE OF CELL AND MOLECULAR SCIENCE, QUEEN MARY, UNIVERSITY OF LONDON, LONDON UK.
Diabetes mellitus (DM) is a disorder characterized by increased concentrations of glucose in the circulation. The glucose level has varied over the years and can presently be determined by either a raised fasting glucose or a raised glucose following oral glucose challenge (Table 1A). Type 1 diabetes, insulin-dependent diabetes mellitus, and type 2 diabetes, noninsulin-dependent diabetes mellitus, represent two distinct diseases. Clinically, the distinction can sometimes be misleading and uncertain. The loss of insulin secretory capacity is most severe in type 1 diabetes while decreased insulin sensitivity is most severe in patients with type 2 diabetes. Secondary diabetes accounts for barely 1%–2% of all new cases. Monogeneic forms of diabetes are rare. Type 1 diabetes patients are considered insulin-dependent at diagnosis, while the type 2 diabetes patients are initially non-insulin-dependent. Ketosis-prone diabetes (KPD) and Latent Autoimmune Diabetes in Adults (LADA) are each exclusive forms of diabetes and have a different natural history from these major types. KPD is diagnosed with the categorical initial clinical feature of ketoacidosis, though subsequently insulin therapy is, for a while, not required. In contrast, LADA can be diagnosed by the co-occurrence of three traits, not one of which is categorical or exclusive to the condition. The three traits are: adult onset non-insulin requiring diabetes, an islet autoantibody such as glutamic acid decarboxylase autoantibodies (GADA) or cytoplasmic islet cell auto antibodies (ICA) and the lack of need for insulin treatment for several months postdiagnosis. LADA is the most prevalent autoimmune diabetes.