REFERENCE LABORATORY CHANGE
Glutamic Acid Decarboxylase (GAD65) Antibody Assay, CSF
Order Code: GD65C
Fee Code: 30955 (CPT 86341)
Reference Laboratory: Mayo GD65C
New Order Code: AG65C
New Reference Lab: ARUP 3002788
LOINC: 42501-7
Collection Instructions: Collect spinal fluid. Send 1 mL (minimum 0.5 mL) in a plastic vial; freeze (preferred) or refrigerate up to 1 week.
Reference Range: 0.0 – 5.0 IU/mL
Glutamic Acid Decarboxylase (GAD65) Antibody Assay, Serum
Order Code: GAD65
Fee Code: 32140 (CPT 86341)
Reference Laboratory: Mayo GD65S
New Order Code: AG65S
New Reference Lab: ARUP 2001771
LOINC: 56540-8
Collection Instructions: Collect specimen in an SST tube. Centrifuge, aliquot 1 mL (minimum 0.5 mL) into a plastic vial and freeze (preferred) or refrigerate up to 1 week.
Reference Range: 0.0 – 5.0 IU/mL
Mayo Clinic Laboratories will discontinue offering Glutamic Acid Decarboxylase (GAD65) Antibody CSF and Serum assays effective October 13, 2026. Mayo Clinic Laboratories recommends a comprehensive neurological phenotype-specific autoimmune/paraneoplastic evaluation based on patient presentation (e.g. encephalopathy, movement disorders, myelopathy, axonal neuropathy, etc.) in place of selective antibody testing. Encephalopathy, Autoimmune Evaluation, CSF (order code ENC2) or Serum (order code ENS2) is recommended for assessing susceptibility to autoimmune (type 1, insulin-dependent) diabetes mellitus and related endocrine disorders.
Requests for Glutamic Acid Decarboxylase (GAD65) Antibody will be sent to ARUP Laboratories. New order codes AG65S and AG65C will be available September 30, 2026.