Table I.

Classification of recommendations in the guidelines

Class of recommendation	Definition	Suggestion of use
Class I	There is scientific evidence and/or general agreement that a specific treatment/procedure is beneficial, useful, and effective	It is recommended/It is indicated
Class II	Scientific evidence is ambiguous and/or there are conflicting opinions as to the usefulness/efficacy of a specific treatment/procedure
Class IIa	Prevailing evidence/opinions confirm the usefulness/efficacy of a specific treatment/procedure	It should be considered
Class IIb	Evidence/opinions do not sufficiently confirm the usefulness/efficacy of a specific treatment/procedure	It may be considered
Class III	There is scientific evidence and/or general agreement that a specific treatment/procedure is useless/ineffective, and in certain cases it may be harmful	It is not recommended