| 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 |
[4] Coovadia's Paediatics & Child Health, edited by Robin J Green Seventh Edition (2014). Chapter 10: Metabolic disorders"Hypernatraemia" page 206, Oxford University Press, South Africa ISBN 978 0 19 90539 4.