Serum or Plasma Immunoassay for Anti-Glutamic Acid Decarboxylase Antibodies (GAD65)

What Is GAD65 Antibody Testing Used For?

GAD65 antibodies are often checked in people suspected of having type 1 diabetes, especially if symptoms like fatigue, frequent urination, or unexplained weight loss appear before classic signs like high blood sugar. It may also be used in cases where diabetes doesn’t respond to insulin treatment or in research about autoimmune diseases affecting the pancreas.

How Is This Test Performed?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where it’s tested using an immunoassay method to detect the presence of GAD65 antibodies. Results are reported as either positive or negative, though some labs may provide a semi-quantitative measure of antibody levels.

What Do My Results Mean?

A positive result suggests a higher likelihood of type 1 diabetes or another autoimmune condition affecting the pancreas. However, it’s not definitive on its own—your doctor may order additional tests, like C-peptide levels or glucose monitoring, to confirm diagnosis or rule out other conditions.

When Might I Need This Test?

Your doctor may recommend this test if you have symptoms of diabetes (like excessive thirst or tiredness), a family history of type 1 diabetes, or if you’re diagnosed with another autoimmune disease. It’s also sometimes used in research or as part of a broader evaluation for unexplained pancreatic issues.