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.
Proteins found in two or three PPD preparations are indicated by the black bars and proteins unique to each individual PPD preparation are indicated by the grey bars.
