I thought it would be useful to have a thread for this. Muscle biopsies aren't currently considered useful in ME/CFS but they are useful in diagnosing other illnesses that might look like ME/CFS. Today I've had a muscle biopsy with 3 samples, in the upper leg. It was painful despite local anesthesia and I could walk only with difficulty afterwards. I believe the method used was of the more invasive kind. It's very useful to have a driver to get home afterwards. I'll share my results once I get them. It will take several months.