BDF in addition to studies cited by ric, John Chia has also published on Enteroviral infection since 2005. He has shown that contrary to mainstream medical thought, you can have a chronic persistent Enteroviral infection for many years. Enteroviruses do not hang around in the blood for long, but migrate quickly to the tissues. Some research has suggested coxsackie has an effect on the immune system and can increase dramatically with cortisol and hormone production. Serology tests vary in type and ability to detect viremia, but are generally not effective unless the viremia is building after an increase in virus production. John Chia has talked about the limitations of serology based tests and it is what prompted his research and tissue biopsy approach. He went looking for it in the place it was known to thrive, the gut. However, he does not test just any gut tissue, but requires tissue from the ant rum area and prepared and sent in a particular manner. So you might need to ask Dr Chia whether the tissue samples you have are suitable. Endosocpy and colonoscopy can be difficult to get through, but arranging a consult with your anaethitist? and providing him or her with information on drug reactions in PWCFS from anesthetic agents, as well as flagging important physical limitations ie: OI, POT, cardiac, myalgia MCS etc will allow your medical team to select a more suitable anesthetic, as well as a request to ensure you are well hydrated with saline and anything else ie magnesium before, during and after the procedure, all make a huge difference to post op recovery. (in fact I think hydration this way is the secret to a speedy recovery from most anesthetic agents whether you have ME or not ) JStfl, what you report regarding improved health after the colonoscopy is I believe, the result of the bowel prep that is prescribed pre op to clean out the bowel. My guess is, that it reduces Enteroviral and other bacterial loads. I am inclined to the view that not enough attention is given to killing off /cleaning out the bowel ( and re populating gut flora) on a regular basis in ME and other patients with chronic GI symptoms. The issue of GI parasites once regularly addressed by our grand parents generation, has all but been forgotten as well.