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HelpTest ID ITCON Itraconazole, Serum
Specimen Required
Collection Container/Tube: Red top (serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial.
Forms
If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.
Secondary ID
81247Useful For
Verifying systemic absorption of orally administered itraconazole
Patients with life-threatening fungal infections
Patients considered at risk for poor absorption or rapid clearance of itraconazole
Method Name
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Itraconazole, SSpecimen Type
Serum RedSpecimen Minimum Volume
0.18 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum Red | Refrigerated (preferred) | 29 days |
| Ambient | 29 days | |
| Frozen | 29 days |
Clinical Information
Itraconazole is a synthetic triazole antifungal drug approved for treatment and prophylaxis of a variety of fungal infections. Its activity results from inhibition of fungal synthesis of ergosterol, an integral component of fungal cell membranes.
Concerns about adequate absorption and drug interactions are some of the major indications for therapeutic drug monitoring. Mean oral bioavailability approximates 55% but is highly variable; absorption can be enhanced by food or acidic drinks. Hepatic enzyme inducers can cause low serum itraconazole levels, and coadministration of these drugs has been associated with itraconazole therapeutic failure.
Itraconazole therapeutic efficacy is greatest when serum concentrations exceed 0.5 mcg/mL for localized infections or 1.0 mcg/mL for systemic infections. An active metabolite, hydroxyitraconazole, is present in serum at roughly twice the level of the parent drug. These concentrations refer to analysis by high-performance liquid chromatography; quantitation by bioassay generates considerably higher apparent drug measurements due to reactivity with the active metabolite.
Reference Values
ITRACONAZOLE (TROUGH):
>0.5 mcg/mL (localized infection)
>1 mcg/mL (systemic infection)
HYDROXYITRACONAZOLE:
No therapeutic range established; activity and serum concentration are similar to parent drug.
Cautions
Enteropathy, H2-histamine receptor blockers, hepatic enzyme inducers, and other variables can result in low to non-detectable serum levels with concomitant high risk of therapeutic failure.
Patients with AIDS and organ transplant recipients receiving immunosuppressive therapy tend to have lower serum itraconazole levels on standard doses and are thus at high risk of therapeutic failure.
Day(s) Performed
Monday through Friday 7a.m., Saturday 3 p.m.
Report Available
1 to 3 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
80189