| 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 |
[5] Benzathine benzylpenicillin (genital ulcer syndrome): Liu HY, Han Y, Chen XS, Bai L, Guo SP, Li L, Wu P, Yin YP. Comparison of efficacy of treatments for early syphilis: A systematic review and network meta-analysis of randomized controlled trials and observational studies. PLoS One. 2017 Jun 28;12(6):e0180001. https://www.ncbi.nlm.nih.gov/pubmed/28658325
Pregnant women, 1st trimester (genital ulcer syndrome): National Department of Health. Guidelines for Maternity Care in South Africa, 2016. http://www.health.gov.za