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Glutamic Acid Decarboxylase Antibody
2001771
Ordering Recommendation

• If pursuing antibody testing to determine autoimmune diabetes mellitus, perform at least 2 antibody tests. In most cases, use glutamic acid decarboxylase antibody in combination with another antibody test. Other antibody tests include IA-2 Antibody (0050202), Insulin Antibody (0099228), Islet Cell Cytoplasmic Antibody, IgG (0050138), and Zinc Transporter 8 Antibody (2006196).
• Most useful to establish autoimmune etiology in previously diagnosed type 1 DM. Do not use to differentiate type 1 DM from type 2 DM, for most cases.

Mnemonic
GAD-AB
Methodology
Semi-quantitative Enzyme-Linked Immunosorbent Assay
Performed
Sun-Fri
Reported
1-3 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
 
Collect
Serum separator tube. 
Specimen Preparation
Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.5 mL) 
Storage/Transport Temperature
Frozen. 
Unacceptable Conditions
Plasma. Grossly hemolyzed specimens. 
Remarks
 
Stability
Ambient: 24 hours; Refrigerated: 1 week; Frozen: 3 months 
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.

Note
CPT Code(s)
83516
Components
Component Test Code*Component Chart NameLOINC
2001772Glutamic Acid Decarboxylase Antibody56540-8
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • 64K Antibody
  • Anti-GAD Antibodies
  • Anti-Glutamic Acid Decarboxylase Ab
  • Beta Cell Antibody
  • Beta-Cell Autoantibody to GAD 65
  • GAD Antibody
  • GAD-65
  • GAD65
  • GAD65 Antibody Assay
  • Glutamate Decarboxylase Antibodies
  • Pancreatic Islet Cell Ab