Adult autistic diagnosis of 4

My son was diagnosed in 2014 at age 25 with autism, on the copy of the diagnosis it says he is a level 4 ,can anyone tell me what 4 means ,is there a scale as to how badly a person is affected, thanks in advance 

Parents
  • Aren't there only 3 levels of autism? Even those aren't very useful. They're all about functioning and whatnot. If your son didn't get diagnosed until 25, then I guess he's probably at the higher functioning end. Sorry I can't give more info but I haven't heard of level 4. Perhaps you should ask the person who diagnosed him.

Reply
  • Aren't there only 3 levels of autism? Even those aren't very useful. They're all about functioning and whatnot. If your son didn't get diagnosed until 25, then I guess he's probably at the higher functioning end. Sorry I can't give more info but I haven't heard of level 4. Perhaps you should ask the person who diagnosed him.

Children
  • Indeed there are only three levels of need in 'ASD' diagnosis (level 1, needing support; level 2, 'substantial support'; level 3, 'very substantial support').  And they probably wouldn't be using those in 2014 in Britain, and even if they were late diagnoses would be almost entirely level 1.

    I think it must refer to something else. Is there any more context in the rest of the sentence?