Amitriptyline and Nortriptyline (Sendout)

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General Information

Lab Name
Amitriptyline, Nortriptyline
Lab Code
RAMNR
Epic Name
Amitriptyline & Noramitriptyline Level (Sendout)
External Test Id
AMTRP
Description

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

Collection Timing: Collect specimen immediately before next scheduled dose (minimum 12 hours after last dose).

Synonyms
AMTRP, Elatrol, Elavil, Endep, Laroxyl, Pamelor, Redomex, Saroten, Trepiline, Tricyclic Antidepressants (TCA), Triptyl, Tryptanol, Tryptizol
Components
Code Name
RAMIT Amitriptyline
RNORT Nortriptyline
RAMINR Amitriptyline, Nortriptyline

Interpretation

Method

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

Reference Range
See individual components
Ref. Range Notes

Reference Values:

Amitriptyline and Nortriptyline, Total Therapeutic Concentration: 80-200 ng/mL
Nortriptyline: 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).

Interferences and Limitations

Cautions:

Due to an analytical interference, patients taking sertraline may have falsely low results and patients taking clomipramine and amlodipine may have falsely elevated results.

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.

Ordering & Collection

Specimen Type
Blood
Collection

5 mL blood in RED TOP tube

Unacceptable: SST/Serum gel tubes

Handling Instructions

Outside Laboratories: Centrifuge sample and transfer serum to a separate plastic vial within 2 hours of collection. Refrigerate serum.

Stability: Refrigerated (preferred): 28 days; Frozen: 28 days; Ambient: 7 days.

Quantity
Requested: 1 mL serum
Minimum: 0.25 mL serum

Processing

Receiving Instructions

Centrifuge sample and transfer serum to a separate plastic vial within 2 hours of collection. Refrigerate serum.

Sendouts:

  • Order Mayo Test: AMTRP.
  • Interfaced: Yes.

Stability: Refrigerated (preferred): 28 days; Frozen: 28 days; Ambient: 7 days.

Misc Sendout

Performance

Lab Department
Sendouts Mayo Lab (RF)(MARF)
Frequency
Performed: Tuesday, Thursday, Sunday. Report Available: 2-5 days.
Available STAT?
No
Performing Location(s)
Sendout Mayo Clinic Laboratories
800-533-1710

200 First Street Southwest
Rochester, MN 55901

Billing & Coding

CPT Codes
80299
LOINC
43106-4
Interfaced Order Code
UOW2140