The analyst that is doubting SRPT's quantification method was the lead manager on the Prosensa IPO. As CG has stated over and over in previous calls, immunostaining is the most common and accepted practice for measuring dystrophin levels, but there are other methods that are evolving in various labs, but none have been validated. They specifically mentioned Western Blot on a recent call, saying that a recent study showed the measurements by Western Blot could not be validated/duplicated by different labs. Beyond the issues with various quantification methods, the issue is not whether a boy showing 50% by immunostaining is really only 45% - the absolute level is not critical - it is a threshold effect and is someone really going to question whether these boys went from little to no dystrophin to something meaningless, but the immunostaining is exaggerating the impact by factors of 2-3 times? The formula here is pretty simple - the drug is designed to patch the genetic code allowing dystrophin to be produced - immunostaining has shown 100% of the boys have increased dystrophin levels after a certain time period on treatment - 100% of the boys that were ambulatory by the time dystrophin was produced are now clinically stable. Measuring dystrophin will never be an exact science, because you can't measure levels in every muscle group at every point in time - allowing that to be the hang-up that keeps this drug from getting approved would be ludicrous.