Tamoxifen and Metabolites

4-Hydroxy-Tamoxifen, Endoxifen, N-desmethyltamoxifen, Nolvadex^®

Test Codes

EPIC: LAB1231986, Beaker: Tamoxifen, Quest: 12761
NOTE: Includes
- Tamoxifen
- N-desmethyltamoxifen
- Endoxifen
- 4-Hydroxy-Tamoxifen

Department

Send Outs

Specimen Collection Criteria

Collect (preferred): One plain Red-top tube.
Acceptable: One Lavender-top EDTA tube or One Pink-top EDTA tube.

Do not use Serum Separator Tubes.

Physician Office/Draw Specimen Preparation

Centrifuge specimen to separate serum or plasma from cells within two hours of collection. Transfer serum or plasma to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Preparation for Courier Transport

Transport: 1.0 mL serum or plasma, refrigerated (2-8°C or 36-46°F). (Minimum: 0.4 mL)

Rejection Criteria

• Serum separator tube(SST).
• Received room temperature.
• Specimens not collected and processed as indicated.

In-Lab Processing

Centrifuge specimen to separate serum or plasma from cells within two hours of collection. Transfer serum or plasma to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Transport: 1.0 mL serum or plasma, refrigerated (2-8°C or 36-46°F). (Minimum: 0.4 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 2 days
Refrigerated (2-8°C or 36-46°F): 30 days
Frozen (-20°C/-4°F or below): 30 days

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 Quest Diagnostics, Wood Dale, IL, forwarded to NMS Labs in Horsham, PA.

Performed

Varies.
Results available in 7-10 days.

Reference Range

By report.

Test Methodology

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

Interpretation

By report.

Clinical Utility

Therapeutic Drug Monitoring.

CPT Codes

80299

Contacts

Last Updated

11/24/2025