Measuring Posaconazole Plasma Concentrations

The blood samples for measuring PCZ C_min were collected for routine care. Only children having achieved steady-state were included in the analysis and PCZ was considered to have achieved a steady-state plasma concentration after at least 7 days of dosing (Lai et al., 2020 (link)). Dose adjustments were taken according to the current guidelines and the manufacturer’s recommendations (Vicenzi et al., 2018 (link)). PCZ trough plasma concentrations were determined using a previously described ultra-high-performance liquid chromatograph-tandem mass spectrometry method (UPLC-MS/MS, Waters, United States) (Jia et al., 2020 (link)). The analytical range was 0.025–5.00 μg mL⁻¹. For the purpose of this study, plasma concentrations ≥0.7 μg mL⁻¹ were considered therapeutic for prophylaxis and ≥1.0 μg mL⁻¹ for treatment (Bernardo et al., 2020 (link)).