Glutamic Acid Decarboxylase Antibodies (GAD65) – Serum

This test helps your healthcare provider check how well your body is working, look for early signs of illness, and decide on the most appropriate care plan for your needs.

Your doctor may order this test if you have symptoms of type 1 diabetes, such as unexplained weight loss, frequent urination, or extreme thirst. It may also be used in people with other autoimmune conditions like autoimmune pancreatitis or cerebellar ataxia, where GAD65 antibodies are sometimes involved.

Before the test, your provider will explain the procedure and give you specific instructions, which may include fasting, avoiding certain medicines, or drinking extra water.

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

Your results are compared with standard reference ranges, and values that fall outside those ranges may point to a condition that needs closer monitoring or follow-up testing.

High levels of GAD65 antibodies suggest an autoimmune response targeting pancreatic cells, which can indicate type 1 diabetes or related conditions. Results alone don’t diagnose diabetes but support further evaluation.

Abnormal results can be caused by infections, chronic diseases, dehydration, medications, recent meals, or normal body changes, so your provider will interpret them alongside your symptoms and history.

Elevated levels are most strongly linked to type 1 diabetes but may also appear in other autoimmune disorders. False positives can occur rarely, so results are often confirmed with additional testing.