| Reference value positive | Reference value negative | |
|---|---|---|
| Method positive (detected) | +/+ Positive Agreement (PA) | −/+ Positive Deviation (PD) |
| Method negative (not detected) | +/− Negative Deviation (ND) | −/− Negative Agreement (NA) |
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.