Mar 14, 2017




Clinical Hub,Tools & Resources,UWHC Lab Test Directory,Toxicology


Nortriptyline (XNOR) Toxicology Lab Test

Name: Nortriptyline

Test Name: Nortriptyline

Health Link Test Code: XNOR

LIS Test Code: NRTP

CPT Code(s): 80335

Methodology: Liquid Chromatography

Clinical Information:


Days Performed: Mon-Fri, dayshift.

In-Lab Turnaround Time: 2 - 3 days.

Patient Preparation:

Patient should be on the same dose for at least five days before collecting a specimen for therapeutic drug monitoring.

Specimen: Blood

Collection Container: Red top

Collection Instructions:

Collect specimen for trough level prior to next dose.

Collection Volume: 4 mL

Pediatric Collection Volume: 4 mL

Stability Ambient:

5 days

Stability Refridgerated:

7 days

Stability Frozen:

1 year

Sample Analyzed: Serum

Testing Volume: 2 mL

Pediatric Testing Volume: 1.5 mL

Specimen Processing:

Centrifuge. Transfer cell-free serum to plastic vial. Refrigerate.

Specimen Transport:

Transport specimen to laboratory. Transport with coolant pack if coming from clinic location.

Unacceptable Criteria:

Specimens collected in red cap with yellow ring (SST) tubes are not acceptable.


Generally effective therapeutic concentration:
18 years and up: 50-150 ng/mL
18 years and up: Total tricyclic concentration in excess of 500 ng/mL

Interpretation Type: Interpretive Guidelines

Critical Calls: yes

Additional Information:

Result of "BELOW DETECTION" indicates that the result is below the method detection limit of 10 ng/mL. The half-life of nortriptyline in an adult is 18-93 hours. It is the major metabolite of amitriptyline (Elavil). Nortriptyline may enhance the effects of alcohol, barbiturates, and other CNS depressants.


This test was developed and its performance characteristics determined by the UWHC Clinical Laboratories. This test meets the standards for clinical testing. This test should not be regarded as investigational or for research use. The US Food and Drug Administration (FDA) has not approved or cleared this test; however, the FDA has determined that such clearance or approval is not necessary.