Measurement of autoantibodies is essential for the management of several peripheral nerve and muscle diseases. The clinical significance of autoantibody testing differs for each antibody. In addition, clinicians must understand several issues including the accuracy of the test, isotype and subclass distribution, and its relationship to disease activity. Moreover, many autoantibody tests are not covered by health insurance. With limited medical resources, clinicians are required to be up-to-date with the latest information to utilize test results in daily practice without misunderstanding.