Performance evaluation of enzyme immunoassay for voriconazole therapeutic drug monitoring with automated clinical chemistry analyzers

OBJECTIVE: Voriconazole is a triazole antifungal developed for the treatment of fungal infectious disease, and the clinical utility of its therapeutic drug monitoring has been evaluated. Recently, a new assay for analyzing the serum voriconazole concentration with an automated clinical chemistry analyzer was developed. We evaluated the performance of the new assay based on standardized protocols. METHODS: The analytical performance of the assay was evaluated according to its precision, trueness by recovery, limit of quantitation, linearity, and correlation with results from liquid chromatography-tandem mass spectrometry (LC-MS/MS). The evaluation was performed with the same protocol on two different routine chemistry analyzers. All evaluations were performed according to CLSI Guidelines EP15, EP17, EP6, and EP9 [1–4]. RESULTS: Coefficients of variation for within-run and between-day imprecision were 3.2–5.1% and 1.5–3.0%, respectively, on the two different analyzers for pooled serum samples. The recovery rates were in the range of 95.4–102.2%. The limit of blank was 0.0049 μg/mL, and the limit of detection of the samples was 0.0266–0.0376 μg/mL. The percent recovery at three LoQ levels were 67.9–74.6% for 0.50 μg/mL, 75.5–80.2% for 0.60 μg/mL, and 89.9–96.6% for 0.70 μg/mL. A linear relationship was demonstrated between 0.5 μg/mL and 16.0 μg/mL (R(2)=0.9995–0.9998). The assay correlated well with LC-MS/MS results (R(2)=0.9739–0.9828). CONCLUSIONS: The assay showed acceptable precision, trueness, linearity, and limit of quantification, and correlated well with LC-MS/MS. Therefore, its analytical performance is satisfactory for monitoring the drug concentration of voriconazole.