You are seeing an 8yo with his mother for increasing behavioral problems and decreasing school performance.  She is concerned about ADHD because several of his friends have been diagnosed and are now on medications and doing well.  On physical exam, he is not making consistent eye contact in the room, shows poor impulse control, and is does not want to speak with you when you ask him questions.  You are now entertaining the possibility of an autism spectrum disorder.

What are the DSM-V diagnostic criteria for an autism spectrum disorder and what are some of the available testing tools?