APPENDIX 1

Infectious Diseases Society of America-US Public Health Service Grading System for Ranking Recommendations in Clinical Guidelines

Category, GradeDefinition
Strength of recommendation
    AGood evidence to support a recommendation for use
    BModerate evidence to support a recommendation for use
    CPoor evidence to support a recommendation
Quality of evidence
    IEvidence from ≥1 properly randomized, controlled trial
    IIEvidence from ≥1 well-designed clinical trial, without randomization; from cohort or case-controlled analytical studies (preferably from >1 center); from multiple time series; or from dramatic results from uncontrolled experiments
    IIIEvidence from opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees
  • Adapted from Canadian Task Force on the Periodic Health Examination. Can Med Assoc J. 1979;121(9):1193–1254.