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HelpOrder Code FLUC 5-Flucytosine, Serum
Reporting Name
5-Flucytosine, SUseful For
Monitoring serum concentration during therapy
Evaluating potential toxicity
May aid in evaluating patient compliance
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumSpecimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions:
1. Serum for a peak level should be collected 1 to 2 hours after oral dose or 30 minutes after intravenous infusion. Trough specimens should be collected immediately prior to next scheduled dose.
2. Within 2 hours of collection, centrifuge, and aliquot serum to plastic vial.
Specimen Minimum Volume
0.3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 28 days | |
| Ambient | 28 days | ||
| Frozen | 28 days |
Reference Values
Therapeutic concentration:
Peak >25.0 mcg/mL (difficult infections may require higher concentrations)
Toxic concentration:
Peak >100.0 mcg/mL
Day(s) Performed
Tuesday, Thursday
CPT Code Information
80299
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Method Description
5-Flucytosine is extracted by mixing serum samples with an acetonitrile and methanol mixture to precipitate proteins. The supernatant is removed and analyzed by an in-house developed liquid chromatography-tandem mass spectrometry method.(Unpublished Mayo method)
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Forms
If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.