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Test Code MEX Mexiletine, Serum

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Reporting Name

Mexiletine, S

Specimen Type

Serum Red


Specimen Required


Patient Preparation: Specimens should only be collected after patient has been receiving mexiletine for at least 3 days. Trough concentrations should be collected just before administration of the next dose.

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube: Red top (serum gel/SST are not acceptable)

Submission Container/Tube: Plastic vial

Specimen Volume: 1.5 mL

Collection Instructions:

1. Draw blood immediately before next scheduled dose.

2. Within 2 hours of collection centrifuge and aliquot serum into a plastic vial.


Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Specimen Stability Information

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

Specimen Minimum Volume

0.5 mL

Day(s) Performed

Monday through Friday

Specimen Retention Time

14 days

Report Available

2 to 5 days

Reference Values

Trough Value

0.5-2.0 mcg/mL: Therapeutic concentration

>2.0 mcg/mL: Toxic concentration

Useful For

Assessing achievement of optimal therapeutic mexiletine concentrations

 

Assessing potential mexiletine toxicity

CPT Code Information

80299

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MEX Mexiletine, S 40779-1

 

Result ID Test Result Name Result LOINC Value
9245 Mexiletine, S 40779-1

Method Description

Protein is precipitated from serum using an organic solvent based internal standard. Following centrifugation, the supernatant is diluted with clinical laboratory reagent water and analyzed by liquid chromatography tandem mass spectrometry.(Unpublished Mayo method)

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Cardiovascular Test Request (T724)

-Therapeutics Test Request (T831)