Dear Dr. Holodniy,

The CDC continues to state that PCRs should not be used for diagnosis, but now does offer advice that if taken, PCRs should begin to show positive after 8-10 days. They then add that negative PCRs should be followed up with 3 and 6 month antibody tests. In light of the growing amount of research studies with PCR screens and the increasing sensitivity of newer generation ELISAs, do you anticipate a change in CDC guidelines re testing windows? At what point post-exposure do you think a DNA PCR with an ELISA can be considered conclusive (ie. >99%) if BOTH tests are negative? Thank you for your consideration in answering my question. Your kindness and concern for others comes across in your responses. I wish you the best of luck in your work.

One can never predict what the federal government might do. There are analyses ongoing as we speak, to determine if the optimal strategy now might be a PCR test at 14-28 days followed by an antibody test at 3 or 6 months. What strategy will have the highest negative predictive value is not clear yet.

MH