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Mexiletine

Mexitil^®

Test Codes

EPIC: LAB6105, Beaker: XMEX, ARUP: 2011539

Department

Send Outs

Specimen Collection Criteria

Collect (preferred specimen): One plain Red-top tube.
Also acceptable: One Lavender-top EDTA tube.

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 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: 0.5 mL)

Rejection Criteria

• Serum Separator (SST) tubes.
• Specimens not collected or processed as indicated.

In-Lab Processing

Centrifuge 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: 0.5 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 48 hours
Refrigerated (2-8°C or 36-46°F): 5 days
Frozen (-20°C/-4°F or below): 2 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.

Performed

Monday, Thursday, Saturday.
Results available in 2-6 days.

Reference Range

Therapeutic: 0.5-2.0 mcg/mL.
Toxic: Greater than 2.0 mcg/mL. 

Test Methodology

Quantitative Liquid Chromatography-Tandem Mass Spectrometry.

Interpretation

By report.

Clinical Utility

Mexiletine is indicated for the treatment of documented ventricular arrhythmias, such as sustained ventricular tachycardia, that in the judgement of the physician, are life-threatening. This assay is used for the therapeutic monitoring and toxicity assessment of mexiletine.

CPT Codes

80299

Contacts

Last Updated

10/3/2023