Very surprising result. I don't think I've ever heard of a blood test for a mental disorder -- at least, not one that actually works.
Be careful about that kind of wording. I and friends who're on the spectrum don't consider it a "mental disorder". It's simply a physiological difference, one that theoretically can be tested for.
Even at her low end of the spectrum, it can cause a lot of distress and pain. I guess it just depends on a person's particular case and the circumstances of their life.