Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Cycle threshold (Ct) values for polymerase chain reaction testing. A lower value corresponds to a higher nasopharyngeal viral load, with 40 being the internal threshold for negativity.
