Serum Anti-Drug Antibody Level (e.g., for Immunotherapy Monitoring)

Why It’s Done

Your doctor may order this test if you’re receiving a medication that can trigger an immune response, such as certain biologics used in cancer or autoimmune treatments. It helps assess whether your body is developing antibodies against the drug, which could affect how well it works or cause side effects.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm to draw blood. The process takes about 5 minutes. If you’re on a blood thinner, let your doctor know before the test.

What the Results Mean

Results are qualitative (present or absent) and indicate whether antibodies were detected. High levels may suggest an immune reaction, while low or absent levels mean no antibodies were found. Your doctor will interpret results in the context of your treatment and symptoms.

Common Uses

This test is primarily used in clinical settings where drugs are administered that can provoke an immune response, such as monitoring patients on targeted cancer therapies (e.g., monoclonal antibodies) or immune-modulating drugs (e.g., for rheumatoid arthritis).