Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

FLUC
82741
F5HAR
57333
Salt Lake City, UT 84108
5-Flucytosine, Serum
Clinical Information: Flucytosine is a broad-spectrum antifungal agent generally used in combined
therapy (often with amphotericin B) for treatment of fungal infections such as cryptococcal meningitis.
Concerns with toxicity (bone marrow suppression, hepatic dysfunction) and development of fungal
resistance limit use of flucytosine, particularly as a monotherapy. The drug is well-absorbed orally, but
can also be administered intravenously (available outside of the United States). There is good correlation
between serum concentrations of flucytosine with both efficacy and risk for toxicity. Because of the
drugâ€s short half-life (3-6 hours), therapeutic monitoring is typically performed at peak levels, 1 to 2
hours after an oral dose or 30 minutes after intravenous administration. Flucytosine is eliminated
primarily as unmetabolized drug in urine. Patients with renal dysfunction may require dose adjustments or
more frequent monitoring to ensure that serum concentrations do not accumulate to excessive levels.
Nephrotoxicity associated with use of amphotericin B can affect elimination of flucytosine when the
drugs are coadministered.
Useful For: Monitoring serum concentration during therapy Evaluating potential toxicity The test may
also be useful to evaluate patient compliance
Interpretation: 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.
Reference Values:
Therapeutic concentration:
Peak >25.0 mcg/mL (difficult infections may require higher concentrations)
Toxic concentration:
Peak >100.0 mcg/mL
Clinical References: 1. Goodwin ML, Drew RH: Antifungal serum concentration monitoring: an
update. J Antimicrobial Chemotherapy 2008;61:17-25 2. Andes D, Pascual A, Marchetti O: Antifungal
therapeutic drug monitoring: established and emerging indications. Antimicrobial Agents Chemotherapy
2009;53(1):24-34
5-HIAA (5-Hydroxyindoleacetic Acid), Random Urine
Reference Values:
5-HIAA mg/g creat
2-10 YRS: 12.0 or less
>10 YRS: 10.0 or less
Creatinine, Random Urine mg/dL
Age mg/dL
0-6 Months 2-32
7-11 Months 2-36
1-2 Years 2-128
3-8 Years 2-149
9-12 Years 2-183
>12 Years
Males: 20-370
Females: 20-320
Test Performed by: Quest Diagnostics Nichols Institute
33608 Ortega Highway
San Juan Capistrano, CA 92690-6130
Current as of January 3, 2013 2:22 pm CST 800-533-1710 or 507-266-5700 or MayoMedicalLaboratories.com Page 34