Diagnostic Testing for Glutamic Acid Decarboxylase (GAD65 Ab) & Insulinoma Antigen 2 (IA-2) autoantibodies is Now Available at the Royal Devon and Exeter NHS Foundation Trust

Autoantibodies recognizing the islet cell antigens glutamic acid decarboxylase (GAD65) and the insulinoma antigen 2 (IA-2) are present in up to 90% of newly diagnosed patients with type 1 diabetes.  The prevalence of GAD/IA-2 autoantibodies is less than 1% in GCK, HNF1A and HNF4A MODY, and testing for these autoantibodies close to diagnosis gives very good discrimination of Type 1 diabetes from MODY (McDonald et al 2011 Diabet Med 28:1028-1033).  The Immunology department at the Royal Devon & Exeter Hospital offers a highly sensitive, automated ELISA method for the quantitative determination of GAD & IA-2 autoantibodies in both serum and plasma samples.

METHODS:
RSR GAD65 autoantibody ELISA Kit
RSR IA-2 autoantibody ELISA Kit

REFERENCE RANGE: Refer to report or laboratory.

SPECIMEN TYPES:

Clotted blood (1 x 7.5ml) for GAD and IA-2 testing only: Please send with your local Pathology request form and a completed GAD & IA2 requestor form to the Immunology Laboratory at the address below.

EDTA blood (minimum 10ml adults; 5ml children; 1ml neonates) for GAD, IA-2 and molecular genetic testing: Please send with a completed MODY request form to the Molecular Genetics Laboratory at the address below.

TRANSPORT OF SPECIMEN: First class post at room temperature

TARGET REPORTING TIME: 2 weeks

COST: £20

Contacts:

References

1. Brooking H, Ananieva-Jordanova R, Arnold C, Amoroso M, Powell M, Betterle C, Zanchetta R, Furmaniak J, Smith BR. A sensitive non-isotopic assay for GAD65 autoantibodies. Clin Chim Acta. 2003 May; 331(1-2):55-9.
2. Nilson E, Ekholm B, Rees Smith B, Törn C, Hillman M. Calcium addition to EDTA plasma eliminates falsely positive results in the RSR GADAb ELISA. Clin Chim Acta. 2008 Feb; 388(1-2):130-4.
3. A comparison of serum and EDTA plasma in the measurement of glutamic acid decarboxylase autoantibodies (GADA) and autoantibodies to islet antigen-2 (IA-2A) using the RSR radioimmunoassay (RIA) and enzyme linked immunosorbent assay (ELISA) kits. Rahmati K, Lernmark A, Becker C, Foltyn-Zadura A, Larsson K, Ivarsson SA, Törn C. Clin Lab. 2008; 54(7-8):227-35.

4.      McDonald TJ, Colclough K, Brown R, Shields B, Shepherd M, Bingley P, Williams A, Hattersley AT, Ellard S. 2011. Islet autoantibodies can discriminate maturity-onset diabetes of the young (MODY) from Type 1 diabetes. Diabet Med 28:1028-1033.