I would say there are rating scales available which could be used to make a diagnosis of Asperger's disorder but they are not mandatory in many parts of the world for making a diagnosis. It would be considered best practise in the western or developed world to use the rating scale but again an experienced clinician might need none.
Based on the fact that you are able to process information quite well (differential diagnoses like OCD
etc being mentioned), communicate so well in written language etc suggests to me that it might not be you who has been diagnosed with the Asperger's syndrome but someone related to you. If I am wrong, then your level of high functioning is a very good prognostic (predictive) factor for your wellness in the future.
I wish all the best for both you and the other person.