Test Overview

Test Methodology

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

Reference Range*

Expected steady state plasma levels in patients receiving recommended daily dosages: 109.0 - 585.0 ng/mL

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Details

Days Test Performed

Monday - Sunday

Analytic Time

7 - 12 days

Soft Order Code


MiChart Code




Laboratory Reference

Mayo FARI (MedTox 771)

Looking to Order a Test?

We’ve provided helpful links to make ordering easy.

Find a Requisition

All specimens should be accompanied by a requisition.

Submitting Specimens

Learn about how to properly label and where to ship specimens.

Order Kits and Supplies

MLabs provides all the supplies necessary for the collection of specimens.

Test FAQ

Visit our provider FAQ and learn about common questions to ordering tests.

Specimen Requirements

Rejection Criteria

Collected in SST or PST


Yellow Top Tube

Normal Volume

2 mL serum or plasma

Minimum Volume

0.25 mL serum or plasma

Additional Information

Test sent to Mayo Clinic Laboratories; performed by MedTox Laboratories

Billing Information

Fee Codes

CPT Code


Have More Billing Questions?

Explore our helpful billing resources:

Billing Resources

Billing FAQ