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Methotrexate

Tube Type

Test ID   LAB481
EPIC Order
  METHOTREXATE
CPT Code(s)   80299
Group/Individual Test   Individual
Laboratory   Core Laboratory
Tube Station   Routine: 30; STAT: 888
Specimen Routine: 2 mL blood/royal blue top tube or plain red top (no gel)
  micro: 500 µL blood/red top (no gel) or red top pediatric bullet; see Comments for additional specimen information
Stability
Unspun: 2 hours
Spun & Separated Room temperature: 2 hrs
Spun & Separated Refrigerator: 14 days
Spun & Separated Frozen: 14 days
Availability 24 hrs/day
Turnaround Time   Routine: 2 hours; STAT: 1 hour.
Reference Range Therapeutic: see Table below
  Toxic: see Table below
Comments
High-dose Therapy--Collect samples at 24, 48, or 72 hours after high dose infusion. Order Methotrexate Level, Pediatric High Dose.
Low-dose Therapy--Collect samples 0.5 hr after IV low dose or 2 hr after PO dosing.
                               Reference Ranges: Methotrexate
Collection Time (Hrs. post dose.) Therapeutic (µm/L)* Toxic (µm/L)
24 <10.0 >10.0
48 <1.0 >1.0
72 <0.1 >0.1
  * Dependent upon malignancy and treatment protocol.  
NOTE: Patients who have received Glucarpidase should not be monitored using this assay due to cross-reactivity. Call the Lab for further information regarding an alternate method.

Reviewed by jcayless on January 06, 2022

Note: Reference ranges provided on this web site are for guidance only, and may not reflect the most recent changes. Refer to laboratory reports for current reference data.

UNC Hospitals
McLendon Clinical Laboratories
101 Manning Drive
Chapel Hill, NC 27514