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24820 Venlafaxine, Serum (VENLA)

Venlafaxine, Serum (VENLA)
Test Code: VENLASO
Synonyms/Keywords
​Ref Lab Code: 83732, Effexor (Venlafaxine), Effexor XR, Venlafaxine (Effexor)
Useful For
Monitoring serum concentration during therapy
 
Evaluating potential toxicity
 
The test may also be used to evaluate patient compliance​
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
Serum​ ​Red Top Tube (RTT) ​ ​1 mL ​0.4 mL ​
Collection Processing Instructions
1. Draw blood immediately before next scheduled dose. Serum drawn from patients 12 hours after an oral dose is appropriate. It is customary to treat the patient at bedtime with a dose, then draw specimen the following morning prior to next dose.
2. Spin down within 2 hours of draw.
Specimen Stability Information
Specimen Type Temperature Time
​Serum Red ​Refrigerated (preferred) ​28 days
​ ​Ambient ​28 days
​ ​Frozen ​28 days
Rejection Criteria
​Serum gel tube ​
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Medical Laboratories Monday, Wednesday; 4:00 pm​ 1-4 days
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)​
Reference Lab
Mayo Clinic Laboratories
Test 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) 2D5 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.
Reference Range Information
Venlafaxine + O-desmethylvenlafaxine: 195-400 ng/mL
Interpretation
Most individuals display optimal response to venlafaxine when combined serum levels of venlafaxine and O-desmethylvenlafaxine are between 195 and 400 ng/mL. Some individuals may respond well outside of this range, or may display toxicity within the therapeutic range, thus interpretation should include clinical evaluation. Risk of toxicity is increased with combined levels >1,000 ng/mL. Therapeutic ranges are based on specimens drawn at trough (ie, immediately before the next dose).
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
​80299 ​ ​ ​ ​
Synonyms/Keywords
​Ref Lab Code: 83732, Effexor (Venlafaxine), Effexor XR, Venlafaxine (Effexor)
Ordering Applications
Ordering Application Description
​Centricity ​Venlafaxine, S (83732)
​Cerner ​Venlafaxine, S (83732)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
Serum​ ​Red Top Tube (RTT) ​ ​1 mL ​0.4 mL ​
Collection Processing
1. Draw blood immediately before next scheduled dose. Serum drawn from patients 12 hours after an oral dose is appropriate. It is customary to treat the patient at bedtime with a dose, then draw specimen the following morning prior to next dose.
2. Spin down within 2 hours of draw.
Specimen Stability Information
Specimen Type Temperature Time
​Serum Red ​Refrigerated (preferred) ​28 days
​ ​Ambient ​28 days
​ ​Frozen ​28 days
Rejection Criteria
​Serum gel tube ​
Useful For
Monitoring serum concentration during therapy
 
Evaluating potential toxicity
 
The test may also be used to evaluate patient compliance​
Reference Range Information
Venlafaxine + O-desmethylvenlafaxine: 195-400 ng/mL
Interpretation
Most individuals display optimal response to venlafaxine when combined serum levels of venlafaxine and O-desmethylvenlafaxine are between 195 and 400 ng/mL. Some individuals may respond well outside of this range, or may display toxicity within the therapeutic range, thus interpretation should include clinical evaluation. Risk of toxicity is increased with combined levels >1,000 ng/mL. Therapeutic ranges are based on specimens drawn at trough (ie, immediately before the next dose).
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Medical Laboratories Monday, Wednesday; 4:00 pm​ 1-4 days
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)​
Reference Lab
Mayo Clinic Laboratories
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
​80299 ​ ​ ​ ​
For most current information refer to the Marshfield Laboratory online reference manual.