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Glutamic Acid Decarboxylase (GAD65) Antibody, Serum/Plasma

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

This test measures the presence of antibodies against the GAD65 protein, which is linked to certain autoimmune conditions affecting the nervous system.

Quick summary

["This test helps diagnose or monitor type 1 diabetes or other autoimmune disorders affecting the pancreas or nerves."]

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

Key facts at a glance

LOINC
110906-5
Short code
GAD65 Ab Msmt CSF
Synonyms
GAD65 Ab Msmt CSF
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test if you have symptoms like unexplained weight loss, frequent urination, extreme thirst, or fatigue that could suggest type 1 diabetes or another autoimmune condition. It may also be used to check for GAD65-related disorders in people with unexplained neurological symptoms.

What to Expect Before the Test

No special preparation is needed. You may have a blood sample drawn from a vein in your arm, similar to other routine blood tests. If you’re on blood-thinning medication, let your provider know before the test.

What the Test Results Mean

Positive results indicate the presence of GAD65 antibodies, which may suggest an autoimmune response targeting the pancreas or nerves. Results alone don’t diagnose a condition but can guide further testing or treatment planning.

Common Conditions Linked to This Test

High levels of GAD65 antibodies are often associated with type 1 diabetes, but they can also appear in other autoimmune conditions like certain neurological disorders or autoimmune pancreatitis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: GAD65 Antibodies Play a Role in Autoimmune Disorders

Short name

GAD65 Antibody

Frequently asked questions

What symptoms might indicate I should get this test?
Symptoms like persistent fatigue, unexplained weight loss, frequent urination, or unusual thirst could signal conditions like type 1 diabetes or other autoimmune disorders that this test helps identify. Always discuss symptoms with your healthcare provider.
How accurate is this test?
This test is highly sensitive and specific for detecting GAD65 antibodies, but results should be interpreted by a healthcare provider in the context of your medical history and symptoms. False positives or negatives can occur rarely.
Can lifestyle changes affect my test results?
While diet or stress may influence autoimmune conditions, they typically don’t directly affect antibody test results. However, consistent test results help track disease activity over time.
  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