We are pleased to announce the release of our anti-GAD65 RIA kit for the determination of autoantibodies to Glutamic Acid Decarboxylase (GAD65Ab) in human serum.

Type 1 diabetes, also known as insulin-dependent diabetes mellitus (IDDM), results from a chronic autoimmune destruction of the insulin-secreting pancreatic beta cells, probably initiated by exposure of genetically susceptible host to an environmental agent. Autoimmune destruction of beta cells is thought to be completely asymptomatic until 80-90% of the cells are lost. This process may take years to complete and may occur at any time in all ages.

During the preclinical phase, this autoimmune process is marked by circulating autoantibodies to beta cell antigens. These autoantibodies are present years before the onset of type 1 diabetes and prior to symptoms. Early studies utilized the immunofluorescence test for islet-cell antibodies (ICA), which has been difficult to standardize and is now replaced by a combination of several radioimmunoassays for antibodies against specific beta cell antigens, such is insulin (IAA), glutamic acid decarboxylase (GAD) and tyrosine phosphatase ICA 512 (IA2).

GAD, the enzyme that catalyzes the conversion of glutamate to GABA, has been identified in two isoforms, molecular weight 65.000 (GAD65) and 67.000 (GAD67). Although GAD autoantibodies are found in type 1 diabetes and in the rare neurological disorder Stiff man syndrome (SMS), the GAD autoantibodies profile in the two diseases differs. Autoantibodies of SMS samples recognize a combination of linear and conformational epitopes of GAD while GAD autoantibodies in samples with type 1 diabetes are predominantly directed to the conformational epitopes. GAD65 autoantibodies are present in 70-80 % of newly diagnosed samples with type 1 diabetes and can be detected many years before onset of the disease.

The combination of the autoantibodies to GAD65 and IA2 is highly relevant for risk assessment of type 1 diabetes in children and adolescence. These tests in combination are more sensitive and predictive than ICA in risk groups, e.g. relatives of type 1 diabetes. GAD65 autoantibodies also occur in a subset of adults with type 2 diabetes (non-insulin-dependent diabetes mellitus). These samples can have pronounced hyperglycemia, and after therapy with oral hypoglycemic agents for several months to years they may become insulin dependent. Therefore, these samples are thought to have a slowly progressive form of type 1 diabetes, sometimes called latent diabetes or latent autoimmune diabetes in adults (LADA). The presence of GAD65 autoantibodies in sera of such samples is a sensitive and specific marker for future insulin dependency.

The anti-GAD65 RIA kit is a direct assay based on the principle of radioligand assays. Highly purified human recombinant GAD65 is labeled with 125Iodine. This tracer is used in excess and bound by the GAD65 autoantibodies of the sample.

This test kit is offered in 50 test and 100 test formats. For research use only. Not for use in diagnostic procedures. View the product pages for more information and pricing:

#KIRM2070 anti-GAD65 RIA (100 tests)