Muscarinic Acetylcholine Receptor Antibody (Serum)

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like muscle weakness, fatigue, or difficulty with eye movements, especially if these symptoms occur alongside other neurological issues. It may also be used to confirm a suspected diagnosis of Lambert-Eaton myasthenic syndrome or other autoimmune conditions affecting nerve-muscle function.

What to Expect Before the Test

No special preparation is typically needed. You may have a blood sample drawn from a vein in your arm. 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 acetylcholine receptor antibodies, which can support a diagnosis of autoimmune-related nerve disorders. However, results alone don’t confirm a specific condition—your provider will consider symptoms, physical exam, and other test results.

Common Symptoms Linked to Positive Results

Muscle weakness, especially in the arms and legs, may worsen with activity. Some people also experience dry mouth, blurred vision, or difficulty swallowing. Symptoms can vary widely and may not always be present.