Hi @
Firestormm, currently it is only diagnostic of functional incapacity of the patient until it undergoes more validation. I have said repeatedly though that I think that it will finally have the right studies for this to be diagnostic, presuming the results are as we expect. That is why I said:
In time I expect this test will become diagnostic.
Currently its most useful for individuals, and is only fully diagnostic of functional incapacity. To prove diagnostic validity of ME requires a much higher standard of evidence. We do not have that yet. That doesn't mean that studies that are being planned cannot do this.
We need to know specificity and sensitivity. Specificity basically means ruling out other causes, sensitivity basically means ruling in ME. In a study with a cohort of healthy controls it was about 95% accurate, which meets the threshold for diagnostic in terms of percentages, but does not meet the other requirements. I think I have read the full paper but I can't recall the details, but here is the press release:
http://www.workwellfoundation.org/wp-content/uploads/2013/08/Press-Release-2-day-CPET-Final1.pdf
(This link is from the foundation research page, but currently does not appear to be working.)
Phoenix Rising had a blog about related stuff here:
http://phoenixrising.me/archives/17902
It notes, and I agree with Simon on this:
I’ve seen no studies showing failure to reproduce CPET results in other illnesses, but it’s probably too soon to say if this is unique to ME/CFS, or just very unusual.
Please note the Workwell Foundation pose this as a
question.
http://www.cebm.net/?o=1025
Now if EBM is used, then for ME to be fully validated also requires multiple prospective cohort studies with follow-up to ensure accuracy, or for the test itself multiple diagnostic studies which are found to be consistent. In one survey I read recently about 75% of doctors (in Australia) approve of the EBM approach, though most don't actually use it ... another issue for EBM.
There is also the issue about what is meant by validation. Validation is usually something that independently verifies findings by another method, at least in science. In terms of medicine it can have different meanings, and be different again for the general public. In part this was why I set up this thread:
http://forums.phoenixrising.me/inde...r-perspectives-in-medicine.26765/#post-408762
In the eyes of the wider medical community, government, the general public and institutions like NICE and the IOM, validation will require substantive research that is not yet done, or dissemination of the current research with some extra justification, or widespread use of the 2 day CPET so that the medical community convinces itself from experience.