Assay

Glutamic acid decarboxylase (GAD) antibodies

Key Words

Glutamic acid decarboxylase antibodies, GAD

 Specimen Collection

Serum (brown)

Turnaround time

28 days

Test indications

GAD antibodies are found in 60% of patients with Stiff man syndrome, usually with high titre. These antibodies are also found in up to 80% of patients with recent onset Type 1 Diabetes Mellitus.  However these antibodies reduce with disease duration.  In the assessment of first degree relatives for autoimmune diabetes, positive results in more than one of the marker antibodies (GAD, Islet cell, IA-2 or insulin) can be associated with the onset of autoimmune diabetes. GAD antibodies are not available as a routine test in established diabetes.

Methodology

ELISA

Interferences

No known methodological interferences

Reference Range

Negative  <10 IU/mL

Positive    ≥10 U/mL

Analytical error

Reference change value

N/A