Saul,
It’s a clinical diagnosis versus a lab test. One consideration is in someone with low neurotransmitters related to dopamine, serotonin and norepinephrine. The OAT has the markers HVA (linked to dopamine), VMA (linked to norepinephrine) and 5-HIAA (linked to serotonin), but these are byproducts of production and not the actually levels. They don’t have anything specific to acetylcholine. None of the neurotransmitter tests just measure what is happening in the brain. They are all related to production throughout the entire body.
Dr. Woeller