| 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 |
[8] Aciclovir, oral: Workowski KA, Bolan GA: Centers for Disease Control and Prevention (CDC). Sexually transmitted diseases treatment guidelines, 2015.MMWR Recomm Rep. 2015;64; RR-3):1-140. http://www.cdc.gov/std/tg2015/tg-2015-print.pdf