Ordering Recommendation

Monitor methotrexate concentration.

Mnemonic
METREXSN
Methodology

Quantitative Immunoassay

Performed

Sun-Sat

Reported

Within 24 hours

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Plain Red. Also acceptable: Green (Sodium or Lithium Heparin), Lavender (EDTA), or Pink (K2EDTA).

Specimen Preparation

Protect from light during collection, storage, and shipment. Separate serum from cells ASAP or within 2 hours of collection. Transfer 3 mL serum to an ARUP Amber Transport Tube. (Min: 1 mL)

Storage/Transport Temperature

Frozen.

Unacceptable Conditions

Serum separator tubes. Specimens not protected from light.

Remarks
Stability

After separation from cells: Ambient: 4 hours; Refrigerated: 2 weeks; Frozen: 6 months

Reference Interval

Effective August 15, 2011

Therapeutic Range
Low dose 0.50-1.00 µmol/L
High dose/24 hours 5.00 µmol/L or less
48 hours 0.50 µmol/L or less
72 hours 0.10 µmol/L or less

Interpretive Data



Compliance Category

FDA

Note
Hotline History
N/A
CPT Codes

80299

Components
Component Test Code* Component Chart Name LOINC
2005406 Methotrexate, Sensitive 14836-1
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • methotrexate drug level
  • methtrexate concentration
  • MTX
Methotrexate, Sensitive