Objectives: As part of a review of guidelines for sleep laboratories, this study summarizes the quality and relevance of evidence cited in support of recommendations on investigations for individuals with sleep disorders.

Methods: Quality of evidence in support of each recommendation was rated as A (from well-conducted, prospective controlled studies), B (from controlled studies and case series, with minor shortcomings), or C (from case series or case series plus controlled studies with substantial limitations). Relevance of the cited evidence was also rated from A to C, in decreasing order of merit.

Results: Of eighty-one recommendations from thirty-seven guidelines, forty-six were supported by evidence from primary studies. Six recommendations were supported by category A evidence, fifteen by category B, and twenty-five recommendations by category C. The cited evidence was highly relevant to eighteen recommendations, of some relevance for twenty-two and of little or no relevance to six. Four recommendations were informed by an absence of available evidence. For the other thirty-one, no evidence was provided in support.

Conclusions: The approach used provided a concise overview of recommendations and supporting evidence for decision-makers. Guidelines on the use of sleep laboratory investigations contain much detailed information, but evidence supporting several recommendations is of limited quality and relevance. Furthermore, good-quality studies of many sleep laboratory applications are needed to assist both health policy formulation and clinical practice.