Mar 14, 2017




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


Doxepin (HCDOX) Toxicology Lab Test

Name: Doxepin

Test Name: Doxepin

Health Link Test Code: HCDOX

LIS Test Code: DOX

CPT Code(s): 80335

Test Component:

Doxepin and metabolite desmethyldoxepin

Methodology: Liquid Chromatography

Clinical Information:


Days Performed: Mon-Fri, dayshift.

In-Lab Turnaround Time: 2 - 3 days.

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: Doxepin plus desmethyldoxepin 150-250 ng/mL
18 years and up: Total concentration of dexepin and desmethyldoxepin >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 doxepin in an adult is 12-23 hours.


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.