GAD65 Antibody (Sendout)

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General Information

Lab Name
Lab Code
1201
Epic Name

Order using Lab Undefined [LABUND]
External Test Id
2001771
Description

Useful For:

  • 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

Ordering Guidance: Although a high positive result (>250 IU/mL) could be consistent with stiff-person syndrome, such a result by this assay has been shown to be insufficiently specific for this diagnosis¹ and is not recommended. For a comprehensive evaluation of patients with suspected stiff-person syndrome (classical or focal forms, such as stiff-limb or stiff-trunk) and progressive encephalomyelitis with rigidity and myoclonus, consider ordering Stiff-Person Spectrum Disorders Evaluation, Serum (Sendout) [OLTG #1108].

References
  1. McKeon et al. GAD65 Antibody ELISA with Extended Reportable Range: Validation and Guidance for Neurological Practice. Annals of Clinical and Translational Neurology, 2026; 0:1–10. https://doi.org/10.1002/acn3.70378
Synonyms
2001771, 64K Antibody, Anti GAD Ab, Anti-Glutamic Acid Decarboxylase Ab, Ataxia, Beta Cell Antibody, GD65S, Glutamic Acid Decarboxylase Antibody, Islet Cell Antibody, Pancreatic Islet Cell Ab, RGAD65, RGD65
Components

Interpretation

Method

Semi-quantitative Enzyme-Linked Immunosorbent Assay

Reference Range
Ref. Range Notes
Reference Interval: 0.0-5.0 IU/mL

Interpretive Data:

A value greater than 5.0 IU/mL is considered positive for glutamic acid decarboxylase antibody (GAD Ab).

This assay is intended for the semi-quantitative determination of the GAD Ab in human serum. Results should be interpreted within the context of clinical symptoms.

References
  1. McKeon et al. GAD65 Antibody ELISA with Extended Reportable Range: Validation and Guidance for Neurological Practice. Annals of Clinical and Translational Neurology, 2026; 0:1–10. https://doi.org/10.1002/acn3.70378

Ordering & Collection

Specimen Type
Blood
Collection

3 mL blood in GOLD SST or RED TOP tube

Handling Instructions

Outside Laboratories:

  • Centrifuge sample and aliquot serum into a separate plastic vial. Freeze serum at -20°C while awaiting shipment. Transport on dry ice.
  • Interface clients will not be able to order this test directly. Clients should submit orders using a paper requisition.

Stability: Frozen (preferred): 3 months; Refrigerated: 1 week; Ambient: 24 hours.

Quantity
Requested: 1 mL serum
Minimum: 0.5 mL serum

Processing

Receiving Instructions

Centrifuge sample and aliquot serum into a separate plastic vial. Freeze serum at -20°C.

Sendouts:

  • Order ARUP Test: 2001771
  • Interfaced: Yes [Interface: 602; Department: ARPZ]

Stability: Frozen (preferred): 3 months; Refrigerated: 1 week; Ambient: 24 hours.

Misc Sendout

Performance

Lab Department
Frequency
Performed: Sunday through Friday. Reported: 1-3 days from sample receipt at ARUP Laboratories.
Available STAT?
No
Performing Location(s)
Sendout ARUP Laboratories, Inc.
800-522-2787

500 Chipeta Way
Salt Lake City, UT 84108

Billing & Coding

Billing Comments

CPT: 86341