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Test Code VENLA Venlafaxine, Serum

Reporting Name

Venlafaxine, S

Useful For

Monitoring serum concentration 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

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Draw blood immediately before next scheduled dose.

2. Blood drawn from patients 12 hours after an oral dose is also appropriate. It is customary to treat the patient at bedtime with a dose, then, collect specimen the following morning prior to next dose.

3. Centrifuge and remove serum from cells within 2 hours of collection.

Specimen Minimum Volume

0.4 mL

Specimen Stability Information

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

Reference Values

Venlafaxine + O-desmethylvenlafaxine: 195-400 ng/mL

Day(s) and Time(s) Performed

Thursday; 4 p.m.

Test Classification

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

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
VENLA Venlafaxine, S 62849-5


Result ID Test Result Name Result LOINC Value
83732 Venlafaxine 9630-5
30195 O-desmethyl Venlafaxine 9630-5
32182 Venlafaxine+O-Desmethylvenlafaxine 62849-5

Clinical Information

Venlafaxine is a serotonin and norepinephrine reuptake inhibitor approved for treatment of major depression, anxiety and panic disorders, and social phobias. It is also used for bipolar disorder, bulimia, post-traumatic stress, obsessive behavior, and attention-deficit disorder. Venlafaxine is converted by cytochrome P450 (CYP) 2D6 to the active metabolite, O-desmethylvenlafaxine. The therapeutic range for venlafaxine includes measurement if O-desmethylvenlafaxine; optimal response is seen when combined concentrations of parent and metabolite are between 195 and 400 ng/mL. Venlafaxine is significantly affected by reduced hepatic function, but only slightly by reduced renal function.


Average elimination half-lives are 5 hours for venlafaxine and 10 hours for O-desmethylvenlafaxine, which are much shorter than many other antidepressants. For this reason, extended release formulations are available. Time to peak serum concentration is 2 hours for the regular product and 8 hours for the extended release product. Common toxicities are mild, including drowsiness, dizziness, nausea, and headache.

Analytic Time

1 day

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

NY State Approved


Method Name

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


If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.