Glutamic Acid Decar Ab 34878

Test Code
GAD AB

Alias/See Also
GAD AB

CPT Codes
86341

Preferred Specimen
1 mL serum

Minimum Volume
1

Instructions
Draw one SST and send serum refrigerated

Transport Container
SST

Transport Temperature
R

Specimen Stability
Room temperature: 7 days
Refrigerated: 14 days
Frozen: 60 days

Methodology
Enzyme Linked Immunosorbent Assay (ELISA)

Setup Schedule
Set up: Sun-Fri p.m.; Report available: 3-5 days

Limitations
GAD-65 antibodies are detected in 20% of diabetic twins who remain disease-free for long periods of time and in 8% of healthy individuals.

Reference Range

<5 IU/mL



Clinical Significance
Glutamic acid decarboxylase (GAD-65) antibody is useful to diagnose insulin dependent diabetes mellitus [Type I diabetes (autoimmune-mediated diabetes)] to assess risk for development of Type I diabetes, to predict onset of Type I diabetes, and risk of development of related endocrine disorders, e.g., thyroiditis. Before clinical onset, Type I diabetes is characterized by lymphocytic infiltration of the islet cells, and by circulating autoantibodies against a variety of islet cell antigens, including GAD-65, IA-2 (a tyrosine phosphatase-like protein), and insulin (IAA).

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153



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.