After I published a blog post outlining the problems with the national testing program, another issue surfaced. A paper in the Annals of Internal Medicine showed that the window of accuracy for testing people for coronavirus infection is very narrow. Patients tested too early or late after the onset of symptoms showed false negative results for the presence of virus. As a result, screening individuals without symptoms would required almost daily testing to identify when they are infected. This would be very difficult to do and not very cost efficient.