{"id":"gad65-antibody","name":"GAD65 Antibody (Glutamic Acid Decarboxylase)","shortName":"GAD65 Ab","aliases":["GAD65 Antibody","Glutamic Acid Decarboxylase Antibody","GAD-65 Ab","GAD Ab","Anti-GAD65","GADA","Glutamic Acid Decarboxylase 65 Autoantibodies","Glutamic Acid Decarboxylase-65 Antibody","GAD65 Autoantibody","Anti-GAD Antibody","GAD65 Ab Assay","Anti-Glutamic Acid Decarboxylase Antibody","Glutamate Decarboxylase Antibodies","GAD Autoantibodies","Beta-Cell Autoantibody to GAD 65","GAD-65","GAD65","GAD65 Antibody Assay"],"abbreviations":["GAD65","GADA","GAD-65"],"loinc":[{"code":"56540-8","primary":true},{"code":"13926-1","primary":false},{"code":"112067-4","primary":false},{"code":"94345-6","primary":false},{"code":"30347-9","primary":false}],"specimen":"serum","units":[{"ucum":"[arb'U]/mL","display":"U/mL"}],"referenceRanges":[{"population":"Adults","low":0,"high":5,"unit":"[arb'U]/mL","unitDisplay":"U/mL","note":"ELISA cutoff used by ARUP (0.0 to 5.0 IU/mL; values above 5.0 are positive) and by Mayo's diabetes profile (less than 5.0 U/mL is negative; 5.0 or more is positive), which matches the cutoff for the RSR ELISA kit in a 2026 cohort. A value of exactly 5.0 is called positive by Mayo. Units and cutoffs depend on the kit, so use the cutoff and flag printed on your own report. Mayo's neurology GAD65 test is a radioimmunoassay reported in nmol/L (0.02 nmol/L or less is the reference). Those results cannot be converted to U/mL and are not covered by this range.","sources":[{"title":"Glutamic Acid Decarboxylase Antibody (ARUP test 2001771)","url":"https://ltd.aruplab.com/Tests/Pub/2001771","publisher":"ARUP Laboratories","year":2026},{"title":"Diabetes Autoimmune Profile (Mayo Clinic Laboratories test FDAIP)","url":"https://www.testcatalog.org/show/FDAIP","publisher":"Mayo Clinic Laboratories (Extended Catalog mirror, testcatalog.org)","year":2026},{"title":"Natural history of a pediatric cohort with islet autoantibody positivity: a single-center retrospective cohort study","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC13126659/","publisher":"Journal of the Endocrine Society 2026;10:bvag087","year":2026}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"Measures antibodies to GAD65, an enzyme in insulin-making cells and nerves; it is one of the islet antibodies used to look for autoimmune (type 1) diabetes.","url":"https://bloodtesttracker.com/markers/gad65-antibody","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}