On Feb. 6, a scientist in a small infectious disease lab on the Centers for Disease Control and Prevention campus in Atlanta was putting a coronavirus test kit through its final paces. The lab designed and built the diagnostic test in record time, and the little vials that contained necessary reagents to identify the virus were boxed up and ready to go. But NPR has learned the results of that final quality control test suggested something troubling — it said the kit could fail 33% of the time.