Although it may surprise laymen, stem cell scientists have not known how to confirm whether a cell was pluripotent or not. In other words, reprogrammed cells, cells from menstrual blood, cells from amniotic fluid, and even cells from teeth have all been touted as equivalent to embryonic stem cells. But scientists did not know how to confirm that they were. "It's kind of been a dirty little secret that we haven't been able to do this before, although it was an obvious thing to try to do," says Jeanne Loring, of The Scripps Research Institute in California. But now that seems to have changed. In a paper published in Nature, Dr Loring has identified key biological indicators that are present in all pluripotent stem cells. The test is also affordable – about US$250. ~ San Diego Union-Tribune, Aug 25