I don't think that online tests are quite as accurate as actually going into a hospital to see a psychiatrist, psychologist, or another specialist. Another person that is knowledgable about Asperger's or autism in general would be able to look at how you socialize (or your knowledge of the social world), what physical problems you may have (such as problems with coordination, problems with gait, etc.), and what other autistic traits you may have. There are some advantages to taking an online test, but then it's always good to have an actual diagnosis that can be documented so that you can have actual proof that you have Asperger's or another autistic spectrum disorder. That can be very useful for qualifying for help at work or school. Not to mention being able to actually know for sure that you have a disorder and what it is and being able to have questions answered that you've had for a long time, plus you now know that other people would have the same problems that you have or had, which is nearly always a good thing.
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I'm 24 years old and live in WA State. I was diagnosed with Asperger's at 9. I received a BS in Psychology in 2011 and I intend to help people with Autistic Spectrum Disorders, either through research, application, or both. On the ?Pursuit of Aspieness?.