| 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 |
[22] Metronidazole, oral: Ravdin JI. Amebiasis. Clin Infect Dis. 1995 Jun;20(6):1453-64; quiz 1465-6. Review. http://www.ncbi.nlm.nih.gov/pubmed/7548493
Metronidazole, oral: Wuerz T, Kane JB, Boggild AK, Krajden S, Keystone JS, Fuksa M, Kain KC, Warren R, Kempston J, Anderson J. A review of amoebic liver abscess for clinicians in a nonendemic setting. Can J Gastroenterol. 2012 Oct;26(10):729-33. http://www.ncbi.nlm.nih.gov/pubmed/23061067