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Posaconazole LC-MS/MS

Test Code: 4200
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Clinical Utility

Patient variability in the pharmacokinetics of posaconazole supports quantitative monitoring of blood drug levels, particularly due to its variable absorption. Monitoring trough levels of posaconazole is suggested in patients with suboptimal nutritional intake (and therefore requiring food and liquid nutritional supplementation), or in patients with gastrointestinal disease such as mucositis, diarrhea, vomiting or GVHD. Monitoring trough levels of posaconazole is also suggested in patients treated with other drugs that either induce or inhibit CYP450 isoenzymes or that serve as substrates for these isoenzymes. Results may be clinically useful to determine if current dosing levels have achieved adequate therapeutic concentrations of posaconazole.

Procedure

Posaconazole is extracted from biological matrix by simple protein precipitation with methanol followed by centrifugation. Chromatographic separation and quantitative analysis of the drug containing supernatant is performed using reversed-phase UPLC-MS/MS method. This test has not been cleared or approved for diagnostic use by the U.S. Food and Drug Administration.

Same day (within 8 - 12 hours from receipt of specimen), Monday through Saturday.

Specimen Type Order Code CPT Code NY Approved Volume Assay Range Special Instructions
serum 4210 80299 Yes 1 mL (min. 0.5 mL) 0.1-10 mcg/mL
  • Collect 4-5 mL whole blood in red top tube.
  • Allow to clot for 30 to 60 minutes and centrifuge to isolate the serum.
  • Transfer 1 mL to a sterile, screw top tube. DO NOT draw in a gel tube.
  • Ship frozen on dry ice Monday through Friday.
Shipping

Ship Monday through Friday. Friday shipments must be labeled for Saturday delivery. All specimens must be labeled with patient's name and collection date. A Viracor Eurofins test requisition form must accompany each specimen. Multiple tests can be run on one specimen. Ship specimens FedEx Priority Overnight® to: Viracor Eurofins, 1001 NW Technology Dr, Lee's Summit, MO 64086.

Causes for Rejection

Specimens received not frozen, whole blood collected in serum or plasma gel, serum gel tubes, or specimen types other than those listed are not accepted.

Specimens are approved for testing in New York only when indicated in the Specimen Information field above.

The CPT codes provided are based on Viracor Eurofins' interpretation of the American Medical Association's Current Procedural Terminology (CPT) codes and are provided for general informational purposes only. CPT coding is the sole responsibility of the billing party. Questions regarding coding should be addressed to your local Medicare carrier. Viracor Eurofins assumes no responsibility for billing errors due to reliance on the CPT codes illustrated in this material.

References

Ashbee HR, Barnes RA, Johnson EM, et al. Therapeutic drug monitoring (TDM) of antifungal agents: guidelines from the British Society for Medical Mycology. J Antimicrob Chemother 2014; 69: 1162-76.

Bryant AM, Slain D, Cumpston A, et al. A post-marketing evaluation of posaconazole plasma concentrations in neutropenic patients with haematological malignancy receiving posaconazole prophylaxis. Int J Antimicrob Agents 2011; 37: 266-9.

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