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Nortriptyline

Pamelor, Aventyl, NORTI

Test Codes

EPIC: LAB8070

Department

Toxicology

Specimen Collection Criteria

Collect: One plain Red-top tube. (Minimum Whole Blood: 2.0 mL)

Do not use Serum Separator Tubes.
Time of Collection: Trough, just prior to the next dose.
Record the exact time of specimen collection on the tube or in the computer system.

Physician Office/Draw Specimen Preparation

Let specimens clot 30-60 minutes. Centrifuge specimen to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged collection tube within two hours of collection. Specimens must be frozen within 24 hours of collection. (Minimum: 0.5 mL serum)

Preparation for Courier Transport

Transport: Centrifuged collection tube, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL serum)

Rejection Criteria

• Serum Separator (SST) tubes.
• Severely lipemic or hemolyzed specimens. 

In-Lab Processing

Let specimens clot 30-60 minutes. Centrifuge specimen to separate serum from cells. Deliver immediately to the appropriate testing station.

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 24 hours
Frozen (-20°C/-4°F or below): 3 months

Specimen Storage in Department Prior to Disposal:

Frozen (-20°C/-4°F or below): 2 months

Laboratory

Royal Oak Toxicology Laboratory

Performed

Monday, Thursday.
Results available the same day as testing performed (1-4 days).

Reference Range

Therapeutic Range: 50.0 – 150.0 ng/mL.
Critical: Greater than 500.0 ng/mL.

Test Methodology

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

This test was developed, and its performance characteristics determined by Beaumont Health. It has not been cleared or approved by the FDA. The Laboratory is regulated under CLIA as qualified to perform high-complexity testing. This test is used for clinical purposes and should not be regarded as investigational or for research.

Interpretation

The concomitant use of medications that induce or inhibit oxidative drug metabolism could affect steady-state serum nortriptyline concentrations.

Clinical Utility

Nortriptyline is a tricyclic antidepressant used for the relief of symptoms of endogenous depression. This assay is used to monitor the therapeutic drug level and evaluate the toxicity of nortriptyline.

CPT Codes

80337 (alternate: G0480).
LOINC: 3872-9

Contacts

Last Updated

5/12/2025