POSACONAZOLE (POS, HPLC) CPT 82491

Posaconazole levels are assayed by high performance liquid chromatography (HPLC). The testing range for posaconazole is from 0.125 – 5.0 µg/ml. There are no established therapeutic ranges. The assay has been validated for plasma levels; however, the drug may be measured in CSF and other biological fluids.

SAMPLE AMOUNT – Send approximately 0.5 - 1.0 ml of sample.

   MICAFUNGIN (MICA, HPLC) CPT 82491

Micafungin levels are assayed by high performance liquid chromatography (HPLC) with fluorescence detection. The testing range for micafungin is 0.05 – 25 µg/ml. The assay has been validated for plasma levels; however, the drug may be measured in CSF and other biological fluids.

SAMPLE AMOUNT – Send approximately 0.5 ml of sample. See Specimen Requirements – (Protect from Light)

   CASPOFUNGIN – (CASPO, HPLC) CPT 82491

Caspofungin levels are assayed by high-performance liquid chromatography (HPLC) with fluorescence detection. The testing range is 0.2 – 10 µg/ml. The lowest limit of quantitation (LOQ) for caspofungin is 0.15 µg/ml. Plasma, urine and other body fluids may be assayed for caspofungin levels, however only caspofungin in plasma has been validated for this laboratory.

   ANIDULAFUNGIN – (ANID, HPLC) CPT 8249

Anidulafungin levels are assayed by high-performance liquid chromatography (HPLC) with fluorescence detection. The testing range is 0.125 – 10 µg/ml. The lowest limit of quantitation (LOQ) for anidulafungin is 0.125 µg/ml. Plasma, urine and other body fluids may be assayed for anidulafungin levels, however only anidulafungin in plasma has been validated for this laboratory.

   ITRACONAZOLE (ITRA) CPT 80299

Bioassay
The bioassay method is suitable for patients on single antifungal therapy. For clinical purposes, the bioassay may be sufficient to determine if the patient is adequately absorbing the drug. Itraconazole bioassay measures total antifungal effect/inhibition in the biological test medium. The testing range for this itraconazole assay is from 0.5 – 20.0 µg/ml. Zones of inhibition less than the lowest standard (0.5 µg/ml) are reported as less than 0.5 (<0.5 µg/ml). Samples with no visible zone of inhibition are reported as “none detected”. In this laboratory, the majority of clinical samples for itraconazole levels are done by bioassay; however, if an itraconazole level by HPLC is required/preferred, the lab would certainly accommodate the request of the ordering physician. Test methodology may be specified on the requisition. The laboratory should be advised of all antifungal agents the patient is currently taking. Itraconazole levels for patients on combination therapy (i.e. 5-FC) are assayed by HPLC.

HPLC (high performance liquid chromatography) CPT 82491
HPLC, an analytical method, is used to assay itraconazole levels for patients on combination therapy as well as for pharmacokinetic studies. The sensitivity range for HPLC is 0.01 – 5.0 µg/ml. The HPLC result is reported in terms of the parent drug, itraconazole, and also itraconazole’s largest metabolite, hydroxy itraconazole. It has been well documented that the two methods, bioassay and HPLC, do not correlate; hence, bioassay values are approximately 3 times higher due to the active metabolite. It is imperative to maintain consistency in terms of assay methodology for each patient. The assay requires 1.0 ml of sample. Collect blood samples in heparin or EDTA tubes (green or lavender tops) and send only the plasma. Store at -20° C.

All fluconazole assays (clinical and pharmacokinetic studies) are done by gas-liquid chromatography. Sensitivity range for fluconazole is 0.25 to 200 µg/ml. Serum samples will usually fall within the lower range (0.25 – 50 µg/ml); however, the fluconazole procedure is linear up to 200 µg/ml which will accommodate anticipated higher levels found in urine samples. Assays can also be done on CSF, bile, peritoneal fluid, dialysate, and other biological fluids.

5-FC’s are done by bioassay. Results are reported from 20 – 160 µg/ml. Panic values of 120 µg/ml or greater are immediately called to the referring laboratory.

Plasma amphotericin – B deoxycholate and/or liposomal preparations of AMB are assayed by HPLC. The HPLC testing range is 0.05 – 10.0 µg/ml. For plasma samples, collect blood in EDTA tubes (lavender tops). See Specimen Requirements – (Protect from Light)

Voriconazole levels are assayed by high performance liquid chromatography (HPLC). The testing range is 0.2 – 10 µg/ml. The lowest limit of quantitation (LOQ) for voriconazole is 0.2 µg/ml. Plasma, CSF, and other body fluids may be assayed for voriconazole levels, however only voriconazole in plasma has been validated for this laboratory.