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HelpTest ID ITCON Itraconazole, Serum
Useful For
Verifying systemic absorption of orally administered itraconazole
The test is indicated in patients with life-threatening fungal infections and in 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 RedCollection Container/Tube: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Specimen Minimum Volume
0.18 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum Red | Refrigerated (preferred) | 14 days |
| Ambient | 14 days | |
| Frozen | 14 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 HPLC; quantitation by bioassay results in 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 nondetectable serum levels with concomitant high risk of therapeutic failure.
AIDS patients and organ transplant patients 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
Tuesday through Saturday; 8 a.m.
Report Available
Same day/1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.CPT Code Information
80299