|Busulfan is chemotherapeutic agent with the potential for severe hepatotoxicity requiring active surveillance of liver status as well as pharmacokinetic monitoring. Busulfan concentrations made with mass spectrometry are not individually considered but instead are used together to calculate an area under the curve (AUC) for risk stratification and therapy guidance. Thus, the evaluation of the analytical error introduced to the AUC should be a guiding force in the investigation of new methods. Monte Carlo simulations were used to characterize the uncertainty associated with AUC under various error scenarios. Increasing analytical variance disproportionately increased the uncertainty on the AUC.