Anti-GAD ELISA Kit (Anti Glutamic Acid Decarboxylase)

INTENDED USE

Human anti-GAD ELISA kit is a reliable quantitative procedure for measuring anti glutamic acid decarboxylase (anti-GAD, GAD65) in human serum. This assay has a minimum sensitivity detection limit of 0.57 u/ml.

BACKGROUND

Glutamic acid decarboxylase (GAD) is an essential marker which has been used to serve for the development of autoimmune diabetes present in adults. This has been useful in helping to identify whether an individual has either latent autoimmune diabetes of adulthood (LADA) or type 1 diabetes. It is well known that the onset of autoimmune diabetes is strongly linked with the presence of autoantibody markers. This antibody is found to be present in over 80% of patients that have type 1 diabetes which has developed during childhood or adolescence.

It is been discovered that anti-GAD and many other antibodies which are directed against pancreatic antigens can be detected for many prior to the clinical onset of autoimmune-mediated diabetes, this provides a clear indication that there must be a long “pre-diabetic” phase which is associated with the autoimmune activity. Other antigens which can also be recognised by anti GAD include GAD 65kDa isoform, GAD65, insulin, islet cell antigen IA-2 and ICA-512.

CONTENT

All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

• Coated Microwells: Bound with anti GAD65 antigen.
• Calibrators 1-6: Concentrations 5, 18, 35, 120, 250, 2000 u/mL (units are NIBSC 97/550), made up from anti-GAD antibody.
• Control 1 (Positive) And Control 2 (Negative).
• Anti-GAD65 Biotin (Lyophilised).
• Reconstitution Buffer.
• Streptavidin Peroxidase (SA-POD)(20x).
• Diluent for SA-POD.
• TMB Peroxidase Substrate.
• Concentrated Wash Solution (10x).
• Stop Solution.

SENSITIVITY

The minimum sensitivity detection limit of human anti glutamic acid decarboxylase (anti-GAD, GAD65) using current anti-GAD ELISA kit was approximately 0.57 U/ml. The dynamic range for this assay is 5.0 – 2000.0 u/ml.

ASSAY CHARACTERISTICS

– Assay Cut Off: Negative (< 5 u/mL), Positive (> 5 u/mL).
– Lower Detection Limit: 0.57 u/mL.
– Intra-Assay Precision: 5.2 – 6.4%
– Inter-Assay Precision: 3.5 – 8.5%
– Clinical Specificity And Sensitivity: In the DASP 2005 study, achieved 98% (n=100) specificity and 92% (n=50) sensitivity.
– Interference: None

REFERENCES

1. Immunology of stiff person syndrome and other GAD-associated neurological disorders. Expert Rev Clin Immunol. (2013) 9 (11): 1043-53. Review. Alexopoulos H. and Dalakas M.C.
2. Spectrum of neurological syndromes associated with glutamic acid decarboxylase antibodies: diagnostic clues for this association. Brain. (2008) 131 (Pt 10): 2553-2563. Saiz et al.
3. The broad clinical phenotype of Type 1 diabetes at presentation. Diabet Med. (2013) 30 (2): 170-8. Merger et al.
4. Expression of recombinant human glutamic acid decarboxylase (GAD) in myeloma cells and enzyme-linked immunosorbent assay (ELISA) for autoantibodies to GAD. J Biochem. (1997) 121 (1): 20-4. Matsuba T., et al.

ADDITIONAL INFORMATION

• Full Name: Anti-GAD ELISA Kit (Anti Glutamic Acid Decarboxylase)
• Reactivity: Human
• Sample Type: Serum
• Sensitivity: 0.57 U/ml

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