The itraconazole bioassay test aids in monitoring antifungal therapy.
The result is not intended to be used as the sole means for clinical diagnosis or patient management decisions.
The bioassay is not accurate if the patient has taken another antifungal agent concurrently or within the prior week.
Concentration determined on a single specimen may not reflect future concentrations because of changes in adherence, drug dosage, route of administration, absorption, or receipt of other medication affecting absorption or metabolism of the azole.
Serum: Collect serum specimens in serum separator or red top tube. Allow blood to clot for 30 minutes, then centrifuge. Pipette serum into a plastic screw cap vial.
Plasma: Collect plasma specimens in an EDTA or heparin tube. Centrifuge for 15 minutes and pipette plasma into a plastic screw cap vial.
Minimum Specimen Requirements
Serum/Plasma: 0.25 mL
Room Temperature/Refrigerated/Frozen: 7 days
Any specimen type other than serum or plasma.
Ship on dry ice or frozen cool pack for next day service. Monday – Friday delivery.
Testing performed on Wednesday. Results released the next morning.
Serum/Plasma: 2 days
Therapeutic ranges have not been established, but levels of at least 3.0 µg/mL have been recommended for treatment. Lower concentrations (1 – 1.5 µg/mL) may be sufficient for prophylaxis.
None Detected: Reported when there is no zone of inhibition.
<0.3 µg/mL: Reported when the zone of inhibition is smaller than that of the lowest calibrator.
Positive: 0.3 – 20.0 µg/mL
>20.0 µg/mL: Reported when the zone of inhibition is greater than the highest calibrator.
Follow-up testing may be necessary if there are changes in treatment, including starting or stopping interacting medications, or suspicion of treatment failure.
Drug levels should be measured after treatment, of at least 2 weeks in dogs and 3 weeks in cats, to reach a steady state.
Preferable to collect blood sample at trough time.