Because there aren't specific medical tests for autism, it's best to get a diagnosis from a physician or psychologist who specializes in developmental disabilities and has experience diagnosing Autism Spectrum Disorders (ASDs).

The diagnosis of autism is made by taking into account the child's complete medical and behavioral history, lengthy observation of the child's behavior, and ruling out other problems that may cause some of the same symptoms. It is important to distinguish autism from other disorders, because a misdiagnosis may result in delayed, inappropriate, or ineffective treatment.