Many of these methods are suboptimal and a high percentage of methods even if published in highly reputed journals can not be reproduced. Variations come from the cell lines used, quality of the pluripotency state to begin with, use of undefined components in media and matrix used , and operator variations ( say a novice from an expert. All these contribute to reproducibility of the study. If researchers use a standard commercial kit – at least the set claims of those commercial kits can be verified clearly and get the results. The suppliers stand behind those products to support.