If you look at this, Raman spectroscopy potential blood based diagnostic test, then it appears to indicate that people with ME/CFS have impaired cellular energy production [https://pubs.rsc.org/en/content/articlelanding/2018/an/c8an01437j#!divAbstract]. I.e. all of those tested had the same result - elevated intracellular phenylalanine.
Same goes for Ron Davis's data from the Seahorse (impaired cellular energy production) and the nano needle [impedence test].
Ron Tompkins pointed out that some diseases have different starting points but converge on a common outcome [OMF Symposium 2018 - my summary].
But, take a disease like a solid tumor cancer. It may look and behave similarly from patient to patient, but there are different metabolic triggers, environmental influences, and each tumor can contain differently mutated genes. And worse, the same treatment can either help or hurt patients due to their unique idiosyncracies.
I've met over 50 other women who all had the exact same "national standard of care" total hysterectomy and carboplatin/paclitaxel chemotherapy. I beat the odds and am cancer free, though others have had up to 3 occurrences, some have died, but I was the only one to end up with ME/CFS.
Same disease, different triggers, and different out comes from the same treatment. This is the fallacy of evidence based medicine. We aren't widgets, and though some factors are the same, our genetics, amount of accumulated DNA damage, level of toxicity, our diets and many other factors will confound standardized treatment.
What we need is data. E.g. does everyone with ME/CFS have elevated intracellular tryptophan (Phair OMF Symposium 2018]?
What we need is a healing treatment plan with a set of tools that can be used to individualize treatment, as is done to optimize patients function and outcomes in cancer, Parkinson's, and autoimmune diseases.