Moderator note: This post has been copied and following posts moved from this thread: Concerns about craniocervical instability surgery in ME/CFS __________________________ Not really clear on how credible this statement is, at least in terms of POTS. I thought there were tachacardia and or/BP change requirements to qualify for a POTS diagnosis. I seem to remember that there are tests for MCAS as well, but I could be wrong; my memory is suspect. But I'm pretty confident about the POTS thing. So why claim that there are large numbers of POTS patients with no evidence of POTS? This strikes me as similar to the myth being promulgated by a cluster of old-time TBD researchers that most patients claiming to have persistent Lyme never had evidence of Lyme in the first place.