Not for diagnosis in what. In this study or in general. And what is this PEM you're describing? The PEM that we only know from the 2-day CPET testing, necessitating that a patient undergo that test to be included in a study that only wants PEM-affected patients? Or the PEM the CDC says they can't define?
After all, so long as the CDC claims that they can't define what PEM is--which is to say they're unwilling to accept any of the testing that's made it into the literature--then how can anyone define exactly what it is. Which leads me to, if I see that there's a study looking at PEM...who's defining what that is, and if the CDC won't accept it, then we're back at square one, what's the difference, and why are we going to make patients sick for something that won't be acceptable as per CDC standards.
I'm trying to be optimistic here. If this study was recruiting for patients with PEM as mandatory, which I think we all agree is a desirable goal, then what besides 2 day CPET would define what PEM is in the first place. Of course, going with Reeves Criteria and doing exercise testing to 'make patients tired' means they're not necessarily looking at patients with PEM in the first place, since they won't know until after they run the testing...assuming they're using a definition of PEM that somebody finds acceptable.
I wish I could be more optimistic. It'd be difficult enough to ponder all this if they did require PEM, which should, I would think, be a minimum requirement. But it isn't. So I don't see much room for optimism, unfortunately. They could have the greatest study designed possible, but if they're not requiring PEM, then how is it an ME/CFS study.