Rating of recommendationTranslation of evidence to recommendationsRating of diagnostic article
A = Established as useful/predictive or not useful/predictive for the given condition in the specified populationLevel A rating requires at least one convincing class I study or at least two consistent, convincing class II studiesClass I: Evidence provided by a prospective study in a broad spectrum of persons with the suspected condition, using a “gold standard” for case definition, where test is applied in a blinded evaluation, and enabling the assessment of appropriate tests of diagnostic accuracy. In addition, there must be adequate accounting for drop-outs with numbers sufficiently low to have minimal potential for bias.
B = Probably useful/predictive or not useful/predictive for the given condition in the specified populationLevel B rating requires at least one convincing class II study or at least three consistent class III studiesClass II: Evidence provided by a prospective study of a narrow spectrum of persons with the suspected condition, or a well designed retrospective study of a broad spectrum of persons with an established condition (by “gold standard”) compared to a broad spectrum of controls, where test is applied in a blinded evaluation, and enabling the assessment of appropriate tests of diagnostic accuracy.
C = Possibly useful/predictive or not useful/predictive for the given condition in the specified populationLevel C rating requires at least two convincing and consistent class III studiesClass III: Evidence provided by a retrospective study where either persons with the established condition or controls are of a narrow spectrum, and where test is applied in a blinded evaluation.
U = Data inadequate or conflicting. Given current knowledge, test/predictor is unprovenClass IV: Any design where test is not applied in blinded evaluation OR evidence provided by expert opinion alone or in descriptive case series (without controls).