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Test Code MEX Mexiletine, Serum

Reporting Name

Mexiletine, S

Useful For

Assessing achievement of optimal therapeutic concentrations


Assessing potential toxicity

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Serum Red

Specimen Required

Container/Tube: Red top

Specimen Volume: 3 mL

Collection Instructions:

1. Samples should only be collected after patient has been receiving mexiletine for at least 3 days.

2. Trough concentrations should be collected just before administration of next dose.

Specimen Minimum Volume

1.1 mL

Specimen Stability Information

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

Reference Values

Therapeutic concentration: 0.8-2.0 mcg/mL (trough value)

Toxic concentration: >2.0 mcg/mL (trough value)

Day(s) and Time(s) Performed

Monday, Wednesday, Friday; 9 a.m.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
MEX Mexiletine, S In Process


Result ID Test Result Name Result LOINC Value
9245 Mexiletine, S 3819-0

Reject Due To


Mild OK; Gross OK


Mild OK; Gross reject


Mild OK; Gross OK


Plasma, serum gel tube


Method Name

High-Performance Liquid Chromatography (HPLC)