Test Overview
Test Methodology

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

Test Usage

Monitor therapeutic drug levels; monitor patient compliance; evaluate doxepin toxicity

Reference Range *

Therapeutic: 75-200 ng/mL; Toxic: > 500 ng/mL; Lethal: 1000 ng/mL (sum of Doxepin and Desmethyldoxepin).

Test Details
Days Set Up
Tuesday
Analytic Time

4 hours

Soft Order Code
DXPN
MiChart Code
Doxepin and Desmethyldoxepin Level
Synonyms
  • Adapin
  • Sinequan
  • Tricyclics, Doxepin
  • DOXEPIN AND DEMETHYLDOXEPIN
  • DEDOX
  • DOX
  • Doxepin and Nordoxepin
  • DEMETHYLDOXEPIN
  • DOXEPIN
  • DOXEPIN RESULT
  • DOXEPIN & DEMETHYLDOXEPIN LEV
  • DOXEPIN + DEMETHYLDOXEPIN LEV
Laboratory
Chemical Pathology
Section
Drug Analysis
Specimen Requirements
Collection Instructions

Collect blood in a red top or green top tube; do not use SST tube. Centrifuge, aliquot serum or plasma into plastic vial as soon as possible and refrigerate.

Alternate Specimen
Lavender top (EDTA plasma) [11/09]
Rejection Criteria
SST or PST tube not acceptable.
Yellow Top Tube
Red Top Tube
Normal Volume
1 mL serum or plasma
Minimum Volume
0.7 mL serum or plasma
Additional Information

Doxepin is a tricyclic antidepressant that has been reported to have less cardiotoxicity than the other TADs. Desmethyldoxepin, the metabolite of doxepin, is also measured.

Billing
CPT Code
80335
Fee Code
20018
LOINC
Z134-7
NY State Approved
No