The CDC paper in Retrovirology had a rather plaintive paragraph about the absence of a panel of bona fide positive and negative control specimens for XMRV detection assays. We have already heard of questions about the 20 positive samples WPI sent to CDC. This did not rate a mention as 'kind cooperation' of competing researchers, a breach of scientific etiquette. Response to a direct question about these results got a classic example of bureaucratic doublespeak in return, before Switzer escaped to vacation without designating anyone else who could respond in his absence. Now, the CFS patient advocate is reporting that there was good reason to avoid mentioning those specimens. He says CDC got 20 solid negatives. WPI had taken the precaution of splitting samples and sending the same panel to another laboratory independent of CDC. PA says this group got 19 solid positives, with one specimen in doubt. (I must emphasize that, in the absence of coherent answers from CDC, we are dealing with unconfirmed rumors.) If this report is even approximately correct, it implies the CDC lab. could not detect XMRV in samples WPI found definitely positive, which another lab confirmed within the limits of experimental error. At this point, we combine this with the published account in the paper to discover that they had evidence their assay was inadequate for the task, then, without modifying their own assay, they created a panel of positive controls they were able to detect. Significantly, they then decided not to confuse the public, or other scientists, with this information. (A story about painting bullseyes around bullet holes comes to mind.) I can scarcely think of anything more likely to damage the scientific credibility of an organization conducting research. One hopes they will take steps to show they did not hide data falsifying their reported validation of their XMRV assay.