Methotrexate Level

Overview

  • EPIC Code:
  • LAB3073
  • Soft Test Code:
  • MTXR

Specimen Collection & Preparation

Test Notes

Specimens from patients who have received glucarpidase (carboxypeptidase G2) as a high dose methotrexate rescue therapy should not be tested using this assay. These specimens have increased serum levels of 4-[[2,4-diamino-6- (pteridinyl)methyl]-methylamino]-benzoic acid (DAMPA)10-12 that result from metabolism of methotrexate by glucarpidase. DAMPA crossreacts with the methotrexate antibody used in this assay, and may continue to circulate for at least five to seven days before accurate measurements of serum methotrexate may return.  Utilize a MISC order for Methotrexate, Post-Glucarpidase. 


Specimen Requirements

1.0 mL Serum from a Red Top Tube in a Plastic Vial


Transport And Storage

14 days Refrigerated


Collection Instructions


Minimum Volume

0.5 mL Serum


Neonatal Volume

Clinical Interpretation

Reference Range:

0.00-0.05 umol/L


Methodology:
  • Homogeneous Enzyme Immunoassay

Production Schedule

Sites Performed
  • Parkview Regional Medical Center
Days Performed
Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Departments
  • Chemistry
Turn Around Time

Same Day/1 to 2 days


Stat Eligible

Coding & Compliance

CDM

01420299


CPT Coding

80299