||Voriconazole has unpredictable pharmacokinetics based on the presence and activity of metabolic enzymes which may vary according to the individual.
Testing is indicated when establishing therapy, upon switching from the IV to oral formulations, in patients failing to respond to therapy and may be helpful in patients where oral absorption is unreliable.|
||Best to use a Plain clotted tube (red top) for collection but if a gel tube (gold top) is used it is important for the laboratory to separate off the serum from the primary gel
tube into a secondary tube as soon as possible. This is because the gel may bind the analyte which may result in an artificially lower result being obtained, interpreted and reported.
||Approximately 1 - 2 ml
|Timing of Samples
||A pre dose sample taken immediately before administration is recommended usually 2-5 days after commencement of therapy.|
|| Prophylaxis and treatment 1-5.5mg/L. Severe infections 2-6mg/L e.g. multifocal, disseminated disease, CNS infections or treatment of pathogens with elevated MICs (e.g. Aspergillus fumigatus MIC 2mg/L).
||< 1 day from time of receipt at Mycology Reference Laboratory (Bristol)