GAD-65 (Glutamic Acid Decarboxylase - 65), IgG
This Test is a blood test used to detect IgG antibodies against the GAD-65 enzyme, which is present in pancreatic beta cells and the nervous system. The presence of these antibodies indicates an autoimmune response where the body mistakenly attacks its own cells.
This test is most commonly used in diagnosing Type 1 diabetes and latent autoimmune diabetes in adults (LADA). It can also be relevant in certain neurological autoimmune disorders such as stiff-person syndrome.
The purpose of this test is to:
- Detect IgG antibodies against the GAD-65 enzyme
- Diagnose autoimmune diabetes (Type 1 and LADA)
- Differentiate between Type 1 and Type 2 diabetes
- Identify autoimmune activity affecting pancreatic or neural tissues
- Support diagnosis of certain neurological autoimmune disorders
GAD-65 (GLUTAMIC ACID DECARBOXYLASE- 65), IGG Test
The GAD-65 IgG (Glutamic Acid Decarboxylase-65 Immunoglobulin G) test detects IgG antibodies directed against the GAD-65 enzyme. GAD-65 is found in pancreatic beta cells that produce insulin and is also present in certain nerve cells.
The test is primarily used to support the evaluation of autoimmune diabetes, including Type 1 diabetes and Latent Autoimmune Diabetes in Adults (LADA). It can be particularly useful when it is unclear whether an adult has Type 1 or Type 2 diabetes.
GAD-65 antibodies may also be associated with certain autoimmune neurological conditions, including stiff-person spectrum disorders and some forms of autoimmune encephalitis or cerebellar disease. In these situations, results should be interpreted carefully alongside symptoms and other investigations.
GAD-65 (GLUTAMIC ACID DECARBOXYLASE- 65), IGG Test is Recommended for Individuals:
- Individuals with suspected Type 1 diabetes
- Adults with newly diagnosed diabetes where the type of diabetes is uncertain
- People suspected of having LADA
- Individuals with diabetes who have unexpectedly low insulin or C-peptide levels
- Patients whose diabetes does not respond as expected to conventional Type 2 diabetes treatment
- Individuals being evaluated for selected autoimmune neurological disorders
- Patients with symptoms suggestive of stiff-person spectrum disorders or other GAD-65-associated neurological conditions
- Individuals whose healthcare provider recommends diabetes autoantibody testing
FAQs
1. What does a positive GAD-65 IgG result indicate?
A positive result means that GAD-65 antibodies have been detected. In a person with diabetes, this can support an autoimmune cause such as Type 1 diabetes or LADA. In neurological conditions, the significance depends on the symptoms and antibody level.
2. Is GAD-65 IgG the same as a general GAD antibody test?
GAD-65 IgG is a specific measurement of IgG antibodies directed against the GAD-65 antigen. It is commonly used when evaluating autoimmune diabetes and certain neurological autoimmune conditions.
3. Is fasting required for the GAD-65 IgG test?
Generally, fasting is not required for this antibody blood test. However, follow any specific instructions given by your healthcare provider or diagnostic laboratory.