Autism spectrum disorders (ASD) are hard to diagnosis for many reasons. There are no tests for it, children have different symptoms, and ASD symptoms are similar to other health problems. Parents are usually the first to notice new or odd behaviors. They may also see forward development backslide or stop. A doctor may notice changes during a routine visit. If problems point to ASD, your child may have one or more of these:

• A physical—The doctor will do an exam. The exam will look for certain features or responses common to ASD. A special skin test may be done to look for tuberous sclerosis.
• Psychological tests—A interview will test how your child answers certain questions. The answers will be compared to others of the same age. Other tests will involve watching your child to test their motor skills, and hand or eye coordination. Their abilities will be compared to children the same age.
• Genetic tests—To look for other genetic problems often linked to ASD such as fragile X syndrome.
• Imaging tests—To look for brain injury.
• EEG—To check the electrical activity of the brain.

The doctor will look for certain factors that suggest ASD. The American Psychiatric Association requires some or all of these:

• Problems interacting with others
• Not sharing
• Problems understanding or keeping relationships
• Not using speech when it should be used
• Repetitive use of objects, movements, or speech
• Inflexible to change
• Intense focus
• Overreaction to sensory information