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Test ID: ITCON
Itraconazole, Serum

Secondary ID A test code used for billing and in test definitions created prior to November 2011

81247

NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Useful For Suggests clinical disorders or settings where the test may be helpful

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 A short description of the method used to perform the test

High-Performance Liquid Chromatography (HPLC)

Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name

Itraconazole, S

Aliases Lists additional common names for a test, as an aid in searching

Itraconazole, Antimicrobial Assay
Sporanox (Itraconazole)

Specimen Type Describes the specimen type needed for testing

Serum Red

Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.

Collection Container/Tube: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.

0.2 mL

Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected

Hemolysis

Mild OK; Gross reject

Lipemia

Mild OK; Gross reject

Icterus

Mild OK; Gross reject

Other

Serum gel tube

Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.

Specimen TypeTemperatureTime
Serum RedRefrigerated (preferred)14 days
 Ambient 14 days
 Frozen 14 days

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

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 Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

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.

Interpretation Provides information to assist in interpretation of the test results

A lower cutoff concentration has not been defined that applies in all cases. The serum concentration must be interpreted in association with other variables, such as the nature of the infection, the specific microorganism, and minimal inhibitory concentration (MIC) results, if available. Localized infections are more likely to respond when serum itraconazole is >0.5 mcg/mL (by HPLC); systemic infections generally require drug concentrations >1.0 mcg/mL.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

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.

Clinical Reference Provides recommendations for further in-depth reading of a clinical nature

1. Andes D, Pascual A, Marchetti O: Antifungal therapeutic drug monitoring: established and emerging indications. Antimicrob Agents Chemother 2009;53(1):24-34

2. Hope WW, Billaud EM, Lestner J, Denning DW: Therapeutic drug monitoring for triazoles. Curr Opin Infect Dis 2008;21:580-586

Method Description Describes how the test is performed and provides a method-specific reference

Itraconazole and hydroxyitraconazole are precipitated from serum using a methanol, glacial acetic acid, and triethylamine mixture; then analyzed by HPLC. (Unpublished Mayo method)

Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.

Monday through Friday; 9:00 a.m.

Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.

Same day/1 day

Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result

3 days

Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

2 weeks

Performing Laboratory Location The location of the laboratory that performs the test

Rochester

Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.

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 Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

80299

LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.

Result IDReporting NameLOINC Code
81247Itraconazole, S10989-2
5122Hydroxyitraconazole18337-6