M-CHAT: Autism Questionnaire
The M-CHAT is an expanded American version of the original CHAT from the U.K (Baron-Cohen et al., 1992; 1996). The M-CHAT has 23 questions using the original nine from the CHAT as its basis. The goal of the ongoing M-CHAT research is to demonstrate adequate psychometric properties of the M-CHAT (sensitivity, specificity, positive and negative predictive power).

DSM – IV Diagnostic Criteria For Autistic Disorder

Diagnostic Criteria For Autism Disorder (ICD 10) (Who 1992)
At least 8 of the 16 specified items must be fulfilled.