Translation of evidence to recommendationsRating of recommendation
Level A rating requires at least one convincing class I study or at least two consistent, convincing class II studies.A = established as effective, ineffective, or harmful for the given condition in the specified population.
Level B rating requires at least one convincing class II study or at least three consistent class III studies.B = probably effective, ineffective, or harmful (or probably useful/predictive or not useful/predictive) for the given condition in the specified population.
Level C rating requires at least two convincing and consistent class III studies.C = possibly effective, ineffective, or harmful (or possibly useful/predictive or not useful/predictive) for the given condition in the specified population.
U = data inadequate or conflicting. Given current knowledge, treatment is unproven.