| Level I | Good quality evidence |
Systematic review of RCTs with consistent findings High quality individual RCT |
| Level II |
Limited quality patient orientated evidence |
Systematic review of lower quality studies or studies with inconsistent findings Low quality clinical trial Cohort studies Case-control studies |
| Level III | Other |
Consensus guidelines, extrapolations from bench research, usual practice, opinion, disease-oriented evidence (intermediate or physiologic outcomes only), or case series |
[12] Azitromycin, oral, 2 g (Severe penicillin allergy): Azithromycin: Pitsouni E, Iavazzo C, Athanasiou S, Falagas ME. Single-dose azithromycin versus erythromycin or amoxicillin for Chlamydia trachomatis infection during pregnancy: a meta-analysis of randomised controlled trials. Int J AntimicrobAgents.2007Sep;30(3):213-21. http://www.ncbi.nlm.nih.gov/pubmed/17596917