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.
Strength of recommendations
| Level A | Useful/predictive or not useful/predictive for given condition in specified population |
| Level B | Probably useful/predictive or not useful/predictive |
| Level C | Possibly useful/predictive or not useful/predictive |
| Level U | Data inadequate or conflicting. Test/predictor is unproven |
Based on ref. (2)
