An official website of the United States government
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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.
Internal and external specificities: Black reference line indicates the cut-point by the Youden index, and grey reference line indicates the proposed cut-point.