Synonyms |
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Glutamic Acid Decarboxylase (GAD)
Antibody
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Clinical
Indications |
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GAD is involved in the control of
release of insulin. However, it is not pancreatic B-cell specific and is found in
cerebellum, sympathetic ganglia and the testis.
Different
isotopes of GAD antibodies have been described in association with IDDM and 'stiff man
syndrome'. In assessment of asymptomatic, high risk, population the presence of antibodies
to GAD (or islet cell or insulin) are associated with high incidence of onset of
Type 1 diabetes within 5 to 7 years.
'Stiff man syndrome' may be associated with malignancy
(paraneoplastic disease) and is characterised by muscle rigidity and spasm. |
Request Form |
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Combined Pathology Blood form
(Yellow/Black)
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Availability |
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Analysed by referral laboratory
if specific criteria met.
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Specific
Criteria |
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Requested by
Consultant (Endocrinologist, Rheumatologist, Neurologist) or agreed with Consultant Biochemist.
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Turnaround
Time |
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1 month
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Specimen |
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Serum
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Volume |
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2 ml
|
Container |
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Yellow top (SST) tube
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Lab. Handling |
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Aliquot and store at 4C
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Causes for
Rejection |
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Not meeting specific criteria.
|
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Interpretation |
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'Stiff man' syndrome: GAD antibody
is present in over 90% of patients with slow, progressive disease of all muscles that
eventually stabilises and 20% of patients with rigidity and spasm restricted to distal
muscles (e.g. leg). Patients with acute progressive disease are GAD antibody negative.
Type 1 diabetes: 70 - 80% of patients with type 1 diabetes
show positive GAD antibodies.
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