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22906 Nortriptyline (NOTRP)

Nortriptyline (NOTRP)
Test Code: NORTSO
Synonyms/Keywords
Aventyl (Nortriptyline), Serum, Nortriptyline, Serum, Pamelor (Nortriptyline), Serum, Sensoval, Aventyl, Pamelor, Norpress, Allegron, and Nortrilen (Nortriptyline), TCA (Tricyclic Antidepressants), Tricyclic Antidepressants (TCA)
Useful For
Monitoring serum concentration during therapy
 
Evaluating potential toxicity
 
The test may also be useful 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 0.25 mL
Collection Processing Instructions
1. Draw specimen immediately before next scheduled dose (minimum 12 hours after last dose).
2. Serum must be separated from cells within 2 hours of draw.
Specimen Stability Information
Specimen Type Temperature Time
Serum​ ​ ​ ​Refrigerated (preferred) 28 days
​Ambient ​7 days
​Frozen ​28 days
Rejection Criteria
Hemolysis Gross
​Lipemia ​Gross
​Icterus ​Gross
Serum Separator Tube (SST)​ ​
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Clinic Laboratories Monday, Wednesday, Friday​ 2-5 days​
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)​
Reference Lab
Test Information
Nortriptyline is a tricyclic antidepressant used for treatment of endogenous depression. It also is a metabolite of the antidepressant amitriptyline. Nortriptyline is used when its stimulatory side effect is considered to be of clinical advantage; amitriptyline is used when the side effect of mild sedation is desirable.
 
Nortriptyline is unique among the antidepressants in that its blood level exhibits the classical therapeutic window effect; blood concentrations above or below the therapeutic window correlate with poor clinical response. Thus, therapeutic monitoring to ensure that the blood level is within the therapeutic window is critical to accomplish successful treatment with this drug.
 
Like amitriptyline, nortriptyline can cause major cardiac toxicity when the concentration is >500 ng/mL, characterized by QRS widening leading to ventricular tachycardia and asystole. In some patients, toxicity may manifest at lower concentrations.​
Reference Range Information
Therapeutic concentration: 70-170 ng/mL
Note: Therapeutic ranges are for specimens drawn at trough (ie, immediately before next scheduled dose). Levels may be elevated in non-trough specimens.
Interpretation
Most individuals display optimal response to nortriptyline with serum levels of 70 to 170 ng/mL. Risk of toxicity is increased with nortriptyline levels >500 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.
 
Therapeutic ranges are based on specimens drawn at trough (ie, immediately before the next dose).
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​80335
Synonyms/Keywords
Aventyl (Nortriptyline), Serum, Nortriptyline, Serum, Pamelor (Nortriptyline), Serum, Sensoval, Aventyl, Pamelor, Norpress, Allegron, and Nortrilen (Nortriptyline), TCA (Tricyclic Antidepressants), Tricyclic Antidepressants (TCA)
Ordering Applications
Ordering Application Description
​Centricity ​Nortriptyline, Serum (NORT)
​Cerner ​Nortriptyline Level (NORT)
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 0.25 mL
Collection Processing
1. Draw specimen immediately before next scheduled dose (minimum 12 hours after last dose).
2. Serum must be separated from cells within 2 hours of draw.
Specimen Stability Information
Specimen Type Temperature Time
Serum​ ​ ​ ​Refrigerated (preferred) 28 days
​Ambient ​7 days
​Frozen ​28 days
Rejection Criteria
Hemolysis Gross
​Lipemia ​Gross
​Icterus ​Gross
Serum Separator Tube (SST)​ ​
Useful For
Monitoring serum concentration during therapy
 
Evaluating potential toxicity
 
The test may also be useful to evaluate patient compliance
Reference Range Information
Therapeutic concentration: 70-170 ng/mL
Note: Therapeutic ranges are for specimens drawn at trough (ie, immediately before next scheduled dose). Levels may be elevated in non-trough specimens.
Interpretation
Most individuals display optimal response to nortriptyline with serum levels of 70 to 170 ng/mL. Risk of toxicity is increased with nortriptyline levels >500 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.
 
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 Clinic Laboratories Monday, Wednesday, Friday​ 2-5 days​
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)​
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​80335
For most current information refer to the Marshfield Laboratory online reference manual.