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Test Code FLUOX Fluoxetine, Serum

Reporting Name

Fluoxetine, S

Useful For

Monitoring serum concentration of fluoxetine during therapy

 

Evaluating potential toxicity

 

Evaluating patient compliance

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum Red


Specimen Required


Collection Container/Tube: Red top (serum gel/SST are not acceptable)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Draw blood immediately before the next scheduled dose (trough).

2. Centrifuge and aliquot serum into plastic vial within 2 hours of collection.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  72 hours

Reference Values

Fluoxetine + Norfluoxetine: 120-500 ng/mL

Day(s) Performed

Wednesday

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

80299

LOINC Code Information

Test ID Test Order Name Order LOINC Value
FLUOX Fluoxetine, S 78437-1

 

Result ID Test Result Name Result LOINC Value
80228 Fluoxetine, S 74982-0
251 Norfluoxetine, S 3868-7
252 Fluoxetine+Norfluoxetine 74948-1

Interpretation

Most individuals display optimal response to fluoxetine when combined serum levels of fluoxetine and norfluoxetine are between 120 and 500 ng/mL. Some individuals may respond well outside of this range or may display toxicity within the therapeutic range; therefore, interpretation should include clinical evaluation. A toxic range has not been well established.

Clinical Reference

1. Hiemke C, Bergemann N, Clement HW, et al. Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology: Update 2017. Pharmacopsychiatry. 2018;51(1-02):9-62

2. Westanmo AD, Gayken J, Haight R: Duloxetine. A balanced and selective norepinephrine- and serotonin-reuptake inhibitor. Am J Health-Syst Pharm. 2005;62(23):2481-2490

3. Waldschmitt C, Vogel F, Pfuhlmann B, Hiemke C. Duloxetine serum concentrations and clinical effects. Data from a therapeutic drug monitoring (TDM) survey. Pharmacopsychiatry. 2009;42(5):189-193

4. Feighner JP, Cohn JB. Double-blind comparative trials of fluoxetine and doxepin in geriatric patients with major depressive disorder. J Clin Psychiatry. 1985;46(3 Pt 2):20-25

5. Kelly MW, Perry PJ, Holstad SG, Garvey MJ. Serum fluoxetine and norfluoxetine concentrations and antidepressant response. Ther Drug Monit. 1989;11:165-170

6. Benfield P, Heel RC, Lewis SP. Fluoxetine: A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in depressive illness. Drugs. 1986;32(6):481-508

7. Wille SM, Cooreman SG, Neels, et al. Relevant issues in the monitoring and toxicology of antidepressants. Crit Rev Clin Lab Sci. 2008;45(1):25-89

Report Available

1 to 8 days

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.