Update Type: Test Code Change
Test Updated: 03/16/2022
Test Overview
Test Methodology

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

Test Usage

Monitor therapeutic drug level

Reference Range *

Therapeutic: 0.5 - 2.0 mcg/mL; Toxic: greater than 2 mcg/mL.

Test Details
Days Set Up
Monday - Saturday
Analytic Time

2 - 6 days

Soft Order Code
MEX
Laboratory
Sendout
Reference Laboratory
Mayo MEX (9245)
Section
Special Testing
Specimen Requirements
Collection Instructions

Collect a trough specimen in a red top tube after patient has been receiving Mexiletine for at least 3 days; do not use SST tube. Centrifuge within 2 hours of collection, aliquot serum into a plastic vial and refrigerate.

Normal Volume
1.5 mL serum
Minimum Volume
0.5 mL serum
Rejection Criteria
SST tube not acceptable.
Additional Information

Test sent to Mayo Clinic Laboratories.

Billing
CPT Code
80299
Fee Code
20039
LOINC
3819-0
NY State Approved
No