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22233 Amitriptyline and Nortriptyline, Serum (AMTRP)

Amitriptyline and Nortriptyline, Serum (AMTRP)
Test Code: AMNORSO
Synonyms/Keywords
Amitriptyline (Elavil), Elavil (Amitriptyline), Elavil, Tryptanol, Endep, Elatrol, Tryptizol, Trepiline, Laroxyl, Saroten, Triptyl, Redomex (Amitriptyline), Nortriptyline (Pamelor), Pamelor (Nortriptyline), Sensoval, Aventyl, Pamelor, Norpress, Allegron, and Nortrilen (Nortriptyline), TCA (Tricyclic Antidepressants), Tricyclic Antidepressants (TCA)
Useful For

Monitoring amitriptyline and nortriptyline serum concentrations during therapy

Evaluating potential amitriptyline and nortriptyline 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

Collection Instructions:

1. Collect specimen immediately before next scheduled dose (minimum 12 hours after last dose).

2. Centrifuge and aliquot serum into plastic vial. Serum must be separated from cells within 2 hours of collection.

Specimen Stability Information
Specimen Type Temperature Time
Serum​ ​ ​ Refrigerated (preferred)​ 28 days​
Ambient ​ 7 days​
Frozen​ 28 days​
Rejection Criteria
Gross hemolysis
​Gross lipemia
​Gross icterus
Serum gel tube​
Interference

This test cannot be performed on whole blood. Serum must be separated from cells within 2 hours of collection; if serum is not removed within this time, tricyclic antidepressant levels may be falsely elevated due to drug release from red blood cells.

Specimens that are obtained from gel tubes are not acceptable because the drug can absorb on the gel and lead to falsely decreased concentrations.

Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Mayo Clinic Laboratories
Monday, Wednesday, Friday 2 to 5 days​ Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Reference Lab
Reference Range Information

AMITRIPTYLINE AND NORTRIPTYLINE

Total therapeutic concentration: 80-200 ng/mL

NORTRIPTYLINE ONLY

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 amitriptyline when combined serum levels of amitriptyline and nortriptyline are between 80 and 200 ng/mL. Risk of toxicity is increased with combined levels are above 500 ng/mL.

Most individuals display optimal response to nortriptyline with serum levels between 70 and 170 ng/mL. Risk of toxicity is increased with nortriptyline levels above 500 ng/mL.

Some individuals may respond well outside of these ranges or may display toxicity within the therapeutic range, thus, interpretation should include clinical evaluation.

Therapeutic ranges are based on specimens collected at trough (ie, immediately before the next dose).

Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​80335
Synonyms/Keywords
Amitriptyline (Elavil), Elavil (Amitriptyline), Elavil, Tryptanol, Endep, Elatrol, Tryptizol, Trepiline, Laroxyl, Saroten, Triptyl, Redomex (Amitriptyline), Nortriptyline (Pamelor), Pamelor (Nortriptyline), Sensoval, Aventyl, Pamelor, Norpress, Allegron, and Nortrilen (Nortriptyline), TCA (Tricyclic Antidepressants), Tricyclic Antidepressants (TCA)
Ordering Applications
Ordering Application Description
​Centricity ​Amitriptyline-Nortriptyline, S (8125)
​Cerner ​Amitriptyline and Nortriptyline Levels (AMT)
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

Collection Instructions:

1. Collect specimen immediately before next scheduled dose (minimum 12 hours after last dose).

2. Centrifuge and aliquot serum into plastic vial. Serum must be separated from cells within 2 hours of collection.

Specimen Stability Information
Specimen Type Temperature Time
Serum​ ​ ​ Refrigerated (preferred)​ 28 days​
Ambient ​ 7 days​
Frozen​ 28 days​
Rejection Criteria
Gross hemolysis
​Gross lipemia
​Gross icterus
Serum gel tube​
Interference

This test cannot be performed on whole blood. Serum must be separated from cells within 2 hours of collection; if serum is not removed within this time, tricyclic antidepressant levels may be falsely elevated due to drug release from red blood cells.

Specimens that are obtained from gel tubes are not acceptable because the drug can absorb on the gel and lead to falsely decreased concentrations.

Useful For

Monitoring amitriptyline and nortriptyline serum concentrations during therapy

Evaluating potential amitriptyline and nortriptyline toxicity

The test may also be useful to evaluate patient compliance

Reference Range Information

AMITRIPTYLINE AND NORTRIPTYLINE

Total therapeutic concentration: 80-200 ng/mL

NORTRIPTYLINE ONLY

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 amitriptyline when combined serum levels of amitriptyline and nortriptyline are between 80 and 200 ng/mL. Risk of toxicity is increased with combined levels are above 500 ng/mL.

Most individuals display optimal response to nortriptyline with serum levels between 70 and 170 ng/mL. Risk of toxicity is increased with nortriptyline levels above 500 ng/mL.

Some individuals may respond well outside of these ranges or may display toxicity within the therapeutic range, thus, interpretation should include clinical evaluation.

Therapeutic ranges are based on specimens collected 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 to 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.