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Immunology Laboratory

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GAD Antibodies

Also known as: GAD65

Antibodies to glutamic acid decarboxylase (anti-GAD) are reliable serological markers of Insulin-dependent diabetes mellitus.

Anti-GAD antibodies in high titre are 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 GAD67); 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.

Specimen requirements

Serum 1ml; plasma is NOT acceptable


  • UK NHS - 15 UKP
  • International and Private - 20 UKP

Laboratory turnaround time

10 days

Laboratory method


Reference range/units

  • Neagtive = 0-4.9U/ml
  • Low Positive = 5-30U/ml

Associated tests

Not applicable

Sample stability

2 months at 2-8ÂșC

Shipping and storage

UK and Ireland

Ambient temperature and first class post. Hays DX users please enquire via email below.


Ambient temperature if courier will deliver within 72 hours otherwise consider refrigerated transport. Freezing is not a requirement.

Ensure delivery Monday to Friday 09:00 - 17:30.

Further information and contact details

For further information, email

Last reviewed:12 September 2022