Days Set Up
Wednesday, Saturday
Analytic Time

3 days

Soft Order Code

Test Updated:



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.

Test Overview

Test Methodology

Quantitative Liquid Chromatography-Tandem Mass Spectrometry

Test Usage

Useful for monitoring compliance and assessing toxicity in overdose situations.

Reference Range

ADULT: Therapeutic: 50 - 300 ng/mL; Toxic: > 750 ng/mL. CHILD (0 - 11 yrs): Therapeutic: 30 - 80 ng/mL; Toxic > 200 ng/mL.

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

Specimen Requirements

Collection Onsite

Collect blood in a red top tube; do not use SST tube.

Collection Offsite

Collect blood in a red top tube; do not use SST tube. Centrifuge, aliquot serum into plastic vial within 2 hours of collection, and refrigerate.

Yellow Top Tube
Red Top Tube
Normal Volume
2 mL serum
Minimum Volume
1 mL serum

Billing Information

CPT Code
Pro Fee Code

Have More Questions?

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.