Glutamic Acid Decarboxylase

Message

Sendout, Mayo test code: GD65S

Test Code

LAB650

Alias/See Also

64K Antibody
Anti-GAD Antibodies
Anti-Glutamic Acid Decarboxylase Ab
Beta Cell Antibody
GAD65 Antibody Assay
Glutamate Decarboxylase Antibodies (GAD65)
Islet cell antibody
Pancreatic Islet Cell Ab
Stiffman Syndrome
Stiff person
Ataxia
GD65S

CPT Codes
86341

Preferred Specimen

1.5 mL serum from a gold serum gel tube

Minimum Volume

1 mL

Other Acceptable Specimens

Red tube

Instructions

Centrifuge and aliquot serum into a plastic vial.

Transport Container

Plastic vial

Transport Temperature

Refrigerated

Specimen Stability

Refrigerated (preferred): 28 days
Frozen: 28 days
Ambient: 72 hours

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Hemolysis: Mild OK; Gross reject
Lipemia: Mild OK; Gross reject
Icterus: Mild OK; Gross reject

Methodology
Radioimmunoassay (RIA)

FDA Status
Approved

Setup Schedule

Monday through Sunday

Report Available

3-6 days

Limitations

Antibodies specific for glutamic acid decarboxylase (GAD65) account for most, but not all, antibodies detected in the islet cell antibody test (IA-2). IA-2 (a protein tyrosine kinase-like protein), insulin, and zinc transporter-8 antibodies are complementary islet cell antibodies.

Reference Range

Included with report

Clinical Significance

Assessing susceptibility to autoimmune (type 1, insulin-dependent) diabetes mellitus and related endocrine disorders (eg, thyroiditis and pernicious anemia).

Distinguishing between patients with type 1 and type 2 diabetes.

Confirming a diagnosis of stiff-man syndrome, autoimmune encephalitis, autoimmune ataxia, brain stem encephalitis, autoimmune epilepsy, autoimmune myelopathy.

Performing Laboratory
Mayo Clinic Laboratories, Rochester, Minnesota

Additional Information
Glutamic Acid Decarboxylase (GAD65) Antibody Assay, Serum

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.