| 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 |
[14] Piperacillin/ Tazobactam and amikacin: Nau R, Kinzig-Schippers M, Sörgel F, Schinschke S, Rössing R, Müller C, Kolenda H, Prange HW. Kinetics of piperacillin and tazobactam in ventricular cerebrospinal fluid of hydrocephalic patients.Antimicrob Agents Chemother. 1997 May;41(5):987-91.http://www.ncbi.nlm.nih.gov/pubmed/9145857