The problem with specified thread count is that you do not know how thick or thin the threads are or, more importantly, how tightly they are twisted. Think about bedding sheets that do carry a thread count description. I think that shopping by brand name is the best option if you cannot see the fabric. It is not fool proof but is pretty reliable. You can go to JoAnn's and buy fabric that is quite nice (and carried higher prices) and some that is very poor (mostly cheap or cheaper). I recently wanted to see the quality of a new line from an online seller- I ordered a charm pack to find out. Several sellers have recently started to emphasize the base fabric they use to print their designs. I think that should be helpful to buyers.