They did not undergo a physical examination nor laboratory testing to exclude the presence of other causes of fatigue, thus potentially affecting our estimate of the incidence of ME/CFS in this population. That is not because physical examination findings or laboratory tests are required to make the diagnosis of this illness: they are not. Rather, physical examination and laboratory testing may have uncovered another illness that would have precluded the diagnosis of ME/CFS. However, our study participants typically had access to regular medical care and are health professionals themselves.
