Nefazodone Level

Serzone

Test Codes

NMS 3145SP, Order as a Miscellaneous Send Out.

Department

Send Outs

Specimen Collection Criteria

Collect (preferred specimen): One plain Red-top tube.

Also acceptable: One Lavender-top EDTA tube or 5.0 mL random urine in a sterile collection container. (Minimum: 0.7 mL)

Do not use Serum Separator Tubes.
Time of Collection: Trough, just prior to the next dose. 

Physician Office/Draw Specimen Preparation

Centrifuge to separate serum or plasma from cells. Transfer serum or plasma to a plastic transport tube and refrigerate (2-8°C or 36-46°F). Maintain urine specimen refrigerated.

Preparation for Courier Transport

Transport: 1.0 mL serum, plasma, or urine, refrigerated (2-8°C or 36-46°F). (Minimum: 0.2 mL)

Rejection Criteria

• Specimens collected in SST tubes.
• Specimens not collected and processed as indicated.

In-Lab Processing

Centrifuge to separate serum or plasma from cells. Transfer serum or plasma to a plastic transport tube and refrigerate (2-8°C or 36-46°F). Maintain urine specimen refrigerated.

Transport: 1.0 mL serum, plasma, or urine, refrigerated (2-8°C or 36-46°F). (Minimum: 0.2 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 14 days
Refrigerated (2-8°C or 36-46°F): 14 days
Frozen (-20°C/-4°F or below): 8 months

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to ARUP Laboratories, Salt Lake City, UT, forwarded to National Medical Services (NMS), Willow Grove, PA.

Performed

Thursday.
Results available in 3-10 days.

Reference Range

By report.

Test Methodology

High Performance Liquid Chromatography (HPLC) / Tandem Mass Spectrometry (LC-MS/MS).

Interpretation

Nefazodone (Serzone) was recently approved for the treatment of depression. Nefazodone appears to have fewer incidences of nervousness, anxiety, tremor and possible sexual dysfunctions than many other antidepressant drugs.

Nefazodone is rapidly and completely absorbed following oral administration with extensive first pass metabolism. Peak levels are typically reached at approximately 1.2 hours with a half-life of 2-4 hours. The pharmacokinetics are non-linear with markedly increased plasma levels seen with increases in dose and over time. Steady state plasma levels are attained within 4-5 days (2).

Clinical Utility

This assay is used for the therapeutic monitoring and toxicity assessment of nefazodone.

Reference

1. Ferry N., et. al., Influence of Hepatic Impairment on the Pharmacokinetics of Nefazodone and Two of its Metabolites After Single and Multiple Oral Doses, Fundam. Clin.Pharmacol., 8 (1994) 463-473.
2. Olin B.R. (editor-in-chief), Drug Facts and Comparisons Monthly Update, Facts and Comparisons, Inc., St. Louis, MO, March 1995, pp. 263Y-264C.

CPT Codes

80338

Contacts

Last Updated

10/10/2023