Table 2

Grading of recommendations19

GradeRecommendation (based on AHCPR 1994)
A (evidence levels Ia, Ib)Requires at least one randomised, controlled trial as part of the body of literature of overall good quality and consistency addressing the specific recommendation
B (evidence levels IIa, IIb, III)Requires availability of well conducted clinical studies but no randomised clinical trials on the topic of recommendation
C (evidence level IV)Requires evidence from expert committee reports or opinions and/or clinical experience of respected authorities. Indicates absence of directly applicable studies of good quality