There is no national standard in the United States. Individual states develop their own systems for inclusive education. The only proviso is ensuring compliance with IDEA. Perhaps you could contact the Council for Exceptional Children (CEC) for more information.
The article below provides an overview of the position of Special Educational Needs Coordinators (SENCOs) in England, which may be of help. Ed policy varies across the UK.
Article ‘I will be “fighting” even more for pupils with SEN’: SENCOs...