DS's dx (actually all 3 of them) were tool-less (if there is such an expression)
After the initial Mis-dx the private Prof spent 3 hours with him and us, just chatting and asking questions of us all (and obviously observing DS's behaviour, responses etc) then issued formal dx of aspergers.
2nd dx by NHS Consultant Psychatrist was impartial - he hadn't seen Prof's written dx - and all he did was ask about behaviours, interview us and son, run though the Gillberg criteria etc. About 4 hours over 3 weekly sessions. Formal dx of Aspergers.
3rd dx was by Clinical Psychologist over 6 months of seeing him 4 days a week all day long. No tools used. Again Aspergers.
Ist private Ed Pysch tested him using WESCII (or somethinglike that) which she said indicated an austistic profile.
2nd private Ed Pysch who was also a trained Clinical Psychologist interviewed him and us and he had to fil out questionnaires. That was the only time his dx was borderline for Aspergers.
At his specialist Further education College for Aspergers students all the trained staff immediately recognised he had Aspergers - just from the initial meeting at his initial suitabity assessment (half a day).
So you can see why I am not a fan of tests. I do not believe that a condition that presents with such a diverse set of bahviours can be diagnosed by tests alone.
Having said that, the only reason his 2nd dx took all of 3 weeks was because the Cons Pysch coudln't get his head around the fact that sone has a good sense of humour [hmmm]