Days Set Up
Daily
Analytic Time

2 hours

MiChart Code
Methotrexate, 4 Hour
Soft Order Code
MTX4

Test Updated:

Synonyms
 

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

FPIA

Test Usage

Monitor therapeutic drug level, evaluate potential toxicity

Reference Range

No precise relationship between methotrexate serum levels and antineoplastic efficacy has been established. Following a 4-6 hour intravenous methotrexate infusion with dosages ranging from 50 mg/m2 - 15 g/m2, a patient with a 24 hr serum level > 5 - 10 umol/L, a 48 hr serum level > 0.5 - 1.0 umol/L, and a 72 hr serum level > 0.2 umol/L is at an increased risk of toxicity if conventional low dose leucovorin rescue is given. In this case, high dose leucovorin rescue would be indicated.

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

Specimen Requirements

Collection Offsite

Collect blood in a red top or green top tube; do not use SST tube. Centrifuge, aliquot serum into a plastic vial, and refrigerate. Cerebrospinal fluid is also an acceptable specimen.

Yellow Top Tube
Normal Volume
0.5 mL serum, plasma, or CSF
Minimum Volume
0.25 mL serum, plasma, or CSF

Billing Information

CPT Code
80299
Pro Fee Code
 
LOINC
3793-7

Have More Questions?

Explore our helpful billing resources:

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.