| 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 |
[24] Snake antivenom criteria: Wood D, Sartorius B and Hift R. Snakebite in north-eastern South Africa: clinical characteristics and risks for severity. S Afr Fam Pract 2016; 58(2):62–67. https://www.tandfonline.com/doi/pdf/10.1080/20786190.2015.1120934