As I've written in the past, I don't consider testing for the Epstein Barr Virus (EBV) to be a reliable way to determine if EBV — which worsens fatigue in CFS/FM — has been reactivated, as most healthy people test positive for EBV.
But here's an interesting finding from a new study: researchers used a new test to detect an antibody for EBV that was negative in healthy people, but positive in most people with CFS who had a reactivation of EBV. In other words, it was an accurate test!
The test isn't on the market yet, but the authors plan to make it available in the future. Though the study only including a specially selected group of 6 CFS patients, this is one more piece of hopeful news. Soon there may be a reliable test for determining which CFS/FM patients will actually benefit from treating for EBV.