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Test Code DXPIN Doxepin and Nordoxepin, Serum

Method Name

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

Specimen Type

Serum Red


Specimen Required


Container/Tube: Red top

Specimen Volume: 1 mL

Collection Instructions:

1. Draw specimen immediately before next scheduled dose (or at a minimum 12 hours after last dose).

2. Serum must be separated from cells within 2 hours of draw.


Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  7 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Reference Values

Therapeutic concentration (doxepin + nordoxepin): 50-150 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.

Day(s) and Time(s) Performed

Monday, Wednesday, Friday; Varies

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

80335

G0480 (if appropriate)

Forms

If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.