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Glutamic Acid Decarboxylase (GAD65) Antibody by Line Blot (Serum/Plasma)

Published: August 9, 2026Updated: August 16, 2026

This test detects antibodies against GAD65, a protein linked to autoimmune conditions affecting the pancreas. It may help diagnose or monitor type 1 diabetes or related disorders.

Quick summary

["This test helps identify immune responses that could affect insulin production in the pancreas."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
83004-2
Short code
GAD65 IgG SerPl Ql Line blot
Synonyms
GAD65 IgG SerPl Ql Line blot
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
line-blot
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 Is Done

Your doctor may order this test if you have symptoms of diabetes, such as frequent urination, extreme thirst, unexplained weight loss, or fatigue. It may also be used in research or specialized clinical settings to assess autoimmune conditions affecting pancreatic function.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from a vein in your arm. If you’re on blood thinners, let your doctor know before the test.

What the Test Measures

The test detects the presence of antibodies (immune proteins) against GAD65, a protein critical for insulin production in the pancreas. Positive results suggest an autoimmune response that may contribute to conditions like type 1 diabetes.

Possible Results and Next Steps

Results may be qualitative (positive/negative) or confirmatory. A positive result indicates a potential autoimmune process, but further testing (like C-peptide levels or glucose monitoring) may be needed to confirm diabetes or other conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

GAD65 antibodies are strongly associated with type 1 diabetes and other autoimmune pancreatic disorders. Early detection can help manage symptoms, prevent complications, and guide treatment decisions, such as insulin therapy or immune-modulating therapies.

Short name

GAD65 Antibody Screening/Confirmation

Frequently asked questions

What does a positive result mean?
A positive result suggests your immune system may be attacking GAD65, a protein needed for insulin production. This could indicate an increased risk for type 1 diabetes or related autoimmune conditions. Your doctor will discuss next steps, such as additional testing or monitoring.
Will this test be done alongside other diabetes-related tests?
Yes, your doctor may order additional tests like fasting blood glucose, hemoglobin A1c, or C-peptide levels to better understand your condition and tailor treatment.
Can lifestyle changes affect this test result?
While lifestyle factors like diet or exercise can influence overall health, they typically do not directly affect antibody test results. However, they may impact symptoms or related conditions like diabetes.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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