Total IgG Antibody to Glutamic Acid Decarboxylase (GAD) Antibodies (Serum)
This test measures the presence of antibodies against glutamic acid decarboxylase (GAD), a protein involved in insulin production. It may be used to help diagnose certain autoimmune conditions.
["This test can help identify autoimmune disorders affecting the pancreas or nervous system."]
Key facts at a glance
- LOINC
- 35280-7
- Short code
- tTG IgA Ser Ql IA
- Synonyms
- tTG IgA Ser Ql IA
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ia
- CPT
- 82784
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your healthcare provider may order this test if you have symptoms like unexplained weight loss, fatigue, or digestive issues that could suggest an autoimmune condition. It may also be used in the evaluation of conditions such as type 1 diabetes or other autoimmune disorders affecting the pancreas or nervous system.
What Does a Positive Result Mean?
A positive result indicates the presence of GAD antibodies in your blood. These antibodies may suggest an autoimmune response targeting GAD, which can be linked to conditions like type 1 diabetes or other autoimmune diseases. However, a positive result alone does not confirm a diagnosis and may require further testing.
What Should You Expect During the Test?
A blood sample will be drawn from a vein, typically in your arm. The blood is then processed to measure the antibody levels. This is a simple procedure that usually takes a few minutes. You may feel slight discomfort, but it is generally well-tolerated.
Common Conditions Monitored or Diagnosed With This Test
This test is often used in the context of diagnosing or monitoring autoimmune conditions that affect the pancreas, such as type 1 diabetes, or other neurological autoimmune diseases. It helps healthcare providers assess immune activity against specific proteins.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
IgG Anti-GAD Antibody
Frequently asked questions
What Are the Normal Results?
How Often Should This Test Be Done?
Can Diet or Lifestyle Affect Test Results?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy