GAD65 Antibody - ELISA
Enzyme Immuno Assay
for the Quantitative Determination of
Antibodies against Glutamic Acid Decarboxylase in serum
single break apart wells
The GAD65 Antibody ELISA depends on the ability of GAD autoantibodies to act divalently and form a bridge between GAD coated on ELISA plate wells and liquid phase GAD-biotin. The GAD-biotin bound is is then quantitated by addition of streptavidin peroxidase and a colorogenic substrate (TMB) with reading of final absorbance at 2 wavelengths (450 and 405 nm) to obtain maximum measuring range (0-2,000 units per ml of WHO reference preparation NIBSC 97/550).
Internal medicine, immunology, endocrinology
Insulin Dependent Diabetes Mellitus (IDDM)
99% of healthy blood donor sera give values of less than 5 Units per ml (NIBSC 97/550) in the assay suggesting that values of 5 U/ml or greater can be considered positive for GAD autoantibodies. However, a provisional cut off for positivity of 10 Units per ml is recommended until individual laboratories have established their own cut off values using appropriate control sera.
In the DASP 2005 study the kit achieved 98% (n=100) specificity.
In the DASP 2005 study the kit achieved 92% (n=50) sensitivity.