Hmmmm, sorry, I think I will kind of disagree with the opinions here. We have tons of biomarkers - we just don't really understand them and none are proven to be diagnostic. Not all biomarkers have to be diagnostic - they can just be measures of physiological states including disease states.Such biomarkers are currently being used to monitor and refine medical treatment by a number of doctors.
Specificity of biomarkers (picking the absolute best) is up to 97%, and sensitivity is at 100%. This of course with markers that have not been adequately tested - no marker has been adequately tested. We are still, many years later, looking at NK cells! Biomarker research needs funding, and like most things to do with ME there simply isn't enough funding or interest - though NK cells are getting a lot of attention currenty.
We also lack an understanding of how to interpret many of these markers. Sure they are abnormal - but what does that really mean? What is the primary consequence? What about secondary consequences? What implications does that have for treatment?
Biochemistry is like a giant jigsaw puzzle of a spider's web, and we still lack many of the pieces and sometimes are looking at it in near darkness. So we fumble to put related pieces together in the right way, and hope that when the light comes on the picture will be there.
Bye, Alex