Serum for GAD, IA-2 and ZnT8 testing only (minimum 500 µL): Please send with your local Pathology request form to Blood Sciences Laboratory.
First class post at room temperature
GAD Positive: >/= 11 U/mL.
£29.04 (all three antibodies)
Autoantibodies recognising the islet cell antigens glutamic acid decarboxylase (GAD 65), Zinc Transporter 8 (ZnT8) 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 and ZnT8 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 Blood Sciences department at the Royal Devon & Exeter Hospital offers a highly sensitive, automated ELISA method for the quantitative determination of GAD, IA-2 and ZnT8 autoantibodies in serum samples.
Anti-GAD antibodies in high titre are also associated with the stiff-person syndrome (60% sensitivity), a rare neurological disease characterised by muscle rigidity and spasms.
Glutamic acid decarboxylase occurs in two isoforms (GAD 65 and GAD 67); although GAD 67 is only expressed in neuronal tissue, the major target antigen in both syndromes is GAD 65, which is the isoform used in this commercial assay.
10 working days
We welcome referrals for GAD. If you are a new requestor please complete the following form: New requestor form
We now also have the option to use NPEx for referral requesting.
Further information about sample requirements for this test can be found here: GAD IA2 ZnT8 – further information
This investigation is performed at the Royal Devon & Exeter Hospital (Wonford) (type 1 DM and stiff-person syndrome).