5-Flucytosine, Antimicrobial Drug Level

Label Mnemonic:	5FLUC
Epic code:	LAB2512
Downtime form:	A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery

Commercial Mailout Laboratory
6240-8 RCP
356-8593

Specimen(s):

Serum

Collection Medium:

Red top tube 5 mL (Clot Activator)

Minimum:

Serum - Draw blood in a plain, red-top tube(s).  Send 1 mL Serum 
for a peak (1-2 hr after oral dose, 30 min after intravenous 
infusion).  
(Absolute Serum Minimum:  0.3 mL)

Trough samples should be drawn immediately prior to next scheduled 
dose.

Rejection Criteria:

Gel separator tubes.

Turn Around Time:

2 days upon receipt at reference laboratory

Reference Range:

Therapeutic concentration: Peak >25.0 mcg/mL (difficult infections may require higher concentrations)

Toxic concentration: Peak >100.0 mcg/mL

Interpretive Data:

Most individuals display optimal response to flucytosine when peak serum levels (1-2 hours after oral dosing) are >25.0 mcg/mL. Some infections may require higher concentrations for efficacy. Toxicity is more likely when peak serum concentrations are >100.0 mcg/mL.

Comments:

Serum is the only acceptable sample.

Methodology:

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

CPT Code:

82542