Glutamic Acid Decarboxylase (GAD65) Immunoglobulin G (IgG) Antibody, Serum
This test measures the level of antibodies against the GAD65 protein in your blood. These antibodies are often linked to certain autoimmune conditions affecting the pancreas.
["This test helps diagnose or monitor type 1 diabetes or related autoimmune disorders."]
Key facts at a glance
- LOINC
- 94345-6
- Short code
- GAD65 IgG+IgM Ser IA-sCnc
- Synonyms
- GAD65 IgG+IgM Ser IA-sCnc
- 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 This Test Might Be Ordered
Your healthcare provider may recommend this test if you have symptoms of type 1 diabetes, such as frequent urination, extreme thirst, unexplained weight loss, or fatigue. It may also be used in cases where other tests are inconclusive or if you have a family history of autoimmune diseases affecting the pancreas.
What to Expect Before the Test
You can prepare for this test by fasting for 8 to 12 hours before the blood draw, unless your provider advises otherwise. Wear comfortable clothing and plan to stay near the testing site for about 15 minutes while the blood is drawn.
What Happens During the Test
A healthcare professional will insert a small needle into a vein in your arm to collect a blood sample. You may feel a slight pinch, but the procedure usually takes less than five minutes. The blood sample will be sent to a lab for analysis.
What Happens After the Test
After the blood is drawn, the needle will be removed, and the area will be cleaned and bandaged. You can usually return to your normal activities immediately. If you experience any unusual symptoms or discomfort, contact your healthcare provider.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
High levels of GAD65 IgG antibodies may indicate an autoimmune response targeting the GAD65 protein in the pancreas. This is strongly associated with type 1 diabetes and other autoimmune conditions like insulin-dependent diabetes mellitus. While not definitive on its own, this test can help confirm a diagnosis or assess disease activity in patients suspected of having these conditions.
Short name
GAD65 IgG Antibody
Frequently asked questions
What does a positive result mean?
Will I need to take any special steps if my results are abnormal?
Can lifestyle changes affect this test result?
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