Joe..if you're really determined to have a neurotransmitter test, there's the brain bio centre in London. It's a clinic which treats mental disorders nutritionally. I went there, but got no results, because they are missing the key (toxins). I don't know how accurate their neurotransmitter test is but my serotonin was low, so i guess that's true enough since i'm in a black hole. It's not cheap either from what i can remember.