ASD is a set of very much heterogeneous symptoms with some common characteristics like lack of eye contact, lack of social guesswork, difficulty in learning unwritten social norms or conventions, missing the sense of personal boundary of other people, lacking or inappropriate gesture, restricted repeatitive and intense interests, etc.
The interview and psychometry methods, sort of, work, still misdiagnosis ain both ways, are common and develop controversies and harasses. Delayed diagnosis is also a fact.
But my question is; do we yet have any "confirmed" and reliable test for ASD particularly those at the "mild" end of the spectrum? Such as a scan-based technique such as MRI/ fMRI/ DTI or say electrophysilology techniques such as EEG or qEEG or molecular tests like DNA blotting or DNA sequencing or Elisa etc does such physical or molecular techniques can characterise ASDs??
Notably, this article says no significant anatomical difference found in a large-scale analysis using ABIDE database.