Is it Validated?
Urbantravels nailed it: FDA approval.
Early adopters?
The part I'm not clear on is what can we DO with the forthcoming WPI assay?
For those of us with enlightened, educated physicians, the WPI test may be sufficient - together with our RNase-L deficiencies, NK cell dysfunction/numbers, documented opportunistic infections, etc - to consider at least more immunomodulatory therapies, and ARV's when indicated. It may be sufficient to encourage some physicians to look for gamma T-cell clonal rearrangements in long-term ME/CFS patients where there may be a suspicion of lymphoma risk. It may be enough to encourage leading-edge neurologists to do SPECT scans... My suspicion though is that the WPI test will be for the "early adopters", and that the majority of patients might need to wait for a government-validated test. Not that that's "right" or "fair"... may just be the way it unfolds.
The majority may have to wait??
But if I'm not mistaken, the majority of patients will still need to wait for an FDA-approved, government-validated test, before we get any financial coverage for this - or wider acceptance by less-informed physicians, of the test as "legit". Which underscores the importance of advocacy to educate the blood folks and other stakeholders on WHY this is urgent - from a scientific perspective.
And of course we have to wait for causality research. And the media response to XMRV - when embargos are finally lifted - may change the way things unfold.