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Cerner Order Name Methotrexate Methotrexate Level, Blood

Performing Laboratory

St. Louis Children's Hospital

Lab Dept

Core Lab

Specimen Requirements

Specimen Type: Blood

Container/Tube

Preferred: Light green-top (Lithium heparin) Vacutainer.

Acceptable: Gold/SST Vacutainer or plain, red-top Vacutainer.

Collection Volume: 1.0 mL (minimum 0.6 mL)

Patient Preparation: None

Sample Rejection:

Grossly hemolyzed specimens.

Mislabeled or unlabeled specimens.

Special Instructions: None

Logistics

Day(s) Test Set Up: Monday-Sunday
Cut-off time: None; performed as received
Turnaround Time: Same day; 2 hours from receipt in lab
Lab Testing Section: Chemistry

Interpretive

Reference Range: No reference range established
Therapeutic methotrexate levels are unique to individual patients and the time a sample is collected. Therefore, a set therapeutic range does not apply.

Methotrexate results are reported as micromoles per liter (micromol/L)

Critical Values: None established
Limitations: Specimens from patients who have received preparations of mouse monoclonal antibodies for diagnosis or therapy may contain human anti-mouse antibodies (HAMA). HAMA present in serum may interfere in immunoassays.
Methodology: Enzyme Immunoassay

Additional Information

For SLCH Laboratory use only

Lab Processing instructions: Centrifuge specimen to separate. If specimen collected in plain, red-top tube aliquot sample into a conical tube for testing(labeling aliquot with specimen type). 
 
Processed Volume: 1.0 mL (minimum 0.3 mL) plasma or serum
 
Analyte Stability:

Ambient - unprocessed: 8 hours

PROCESSED

Ambient: 8 hours
Refrigerated: 3 days
Frozen: 6 months
 
NOTES: Reject due to gross hemolysis (slight to moderate okay)

General Information

EPIC order name: Methotrexate Level (EPIC Test# LAB481)
Cerner order name: Methotrexate
CPT Codes: 80204
LOINC Value: 14836-1
Synonyms:

Last Reviewed

November 2024