NORTRIPYLINE, serum (087-0668)
Synonyms: Aventyl, Pamelor
CPT 4 Code: 80182
Test Order Mnemonic: NORTRIP
Lab: Clinical Chemistry
Request Form: Special Chemistry Form 2
Collection: Routine venipuncture. The optimal time
for collection of specimens for steady-date levels is between 10 and 14 hours after the
last dose of medication for patients taking antidepressants once a day, and just before
the morning dose for patients who are on a divided dose schedule.
Storage Instructions: Store at 2-8°C. Centrifuge
the specimen, remove serum from red cells within 4 hours of collection and freeze in a
plastic vial.
Causes for Rejection: Serum allowed to remain on the
clot for more than 4 hours, blood collected in a SST/serum separator tube
Availability: Samples are received 24 hours per day
at Sample Management, 5.136 McCullough.
Turnaround Time: Routine: 3-5 days; test is
performed Tuesdays and Thursdays
Special Instructions: Blood samples received in the
TDM laboratory before noon on the day of analysis will be included on the run. STAT
requests after 4:00 PM require the approval of the director or pathology resident on call.
Metabolites of cyclobenzaprine (Flexeril) may cause interference. Nortriptyline cannot be
quantitated if the patient is also on cyclobenzaprine. Some of the phenothiazines may also
interfere.
Specimen: Blood
Volume: 7 mL blood
Minimum Volume: 1 mL serum
Container: Red-topped tube. Do not use
SST/serum separator tubes.
Reference Ranges: Therapeutic Range: 50-150 ng/mL
Critical Values: Potential toxicity: > 500 ng/mL
