GAD Antibodies (Glutamic Acid Decarboxylase)
Immunology
Sample and container requirements
Serum
Minimum volume required
4 ml Blood
Special requirements
none
Patient preparation
None
Sample viability
Store at 4oC
Turnaround time
21-28 days
Reference range
0-5 IU/mL Negative
Clinical guidance
Anti GAD antibodies found in >60% of patients with Stiff Man syndrome, can also be found in patients with Type 1 diabetes. Note, this assay detects anti-GAD65 antibodies. Patients with stiff person syndrome may have antibodies to GAD67. Although there is 65% homology to GAD65, in patients with SPS, false negative anti-GAD by this method may occur. Please contact Immunology in such cases to discuss further testing. https://labtestsonline.org.uk/tests/islet-autoantibodies-diabetes
Notes
Images to go here
This information was last updated on 19 August 2026