Itraconazole Drug Level

Label Mnemonic:	ICZ
Epic code:	LAB3453
Downtime form:	Doctor/Provider Orders - Pathology Core and Specialty Care Nursery

Commercial Mailout Laboratory
6240-8 RCP
356-8593

Specimen(s):

Serum

Specimen Instructions:

The "Absolute Minimum" listed above, allows for the assay to be performed once. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected; we suggest a full red top for this test to be completed.

Collection Medium:

Red top tube 5 mL (Clot Activator)

Minimum:

Preferred Minimum: 1 mL serum
Absolute Minimum: 0.2 mL serum

Rejection Criteria:

Serum gel tube is not acceptable.

Turn Around Time:

3 days upon receipt at reference laboratory

Reference Range:

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.

Interpretive Data:

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.

Comments:

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.

Methodology:

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

CPT Code:

80189