The Autism Spectrum Quotient Test is an actual diagnostic questionnaire designed to measure the expression of Autistic traits in an individual (age 16+) through self-assessment.
This is one my psychologist used for my screening. Initially, I took it from Embrace Autism, which is by far my favorite. I've also found the test in other places on the internet noted below.
Autism Spectrum Quotient (AQ) with online scoring from Embrace Autism
Autism Spectrum Quotient (AQ) with online scoring on psychology-tools.com
Autism Spectrum Quotient child version (in various languages) from the University of Cambridge Autism Research Centre
The AQ-10 is a shorter, brief screening tool that could indicate if one should be further tested for Autism, or not. Again, Embrace Autism does a fantastic job at providing commentary behind this.
AQ-10 with online scoring on Embrace Autism
AQ-10 printable PDF from the University of Cambridge Autism Research Centre