Background. Therapeutic drug monitoring (TDM) of aminoglycosides and vancomycin is used to prevent oto- and nephrotoxicity in neonates. Analytical and non-analytical factors potentially influence dosing recommendations. Aim. To determine the impact of analytical variation (imprecision and bias) and non-analytical factors (accuracy of drug administration time, use of non-trough concentrations, biological variation and dosing errors) on […]