Methotrexate Lvl (MTX)
Department: Chemistry
Test Synonym(s): LAB481, MTX
CPT Codes: 80299
Reference Range: 0-150yrs: 24hr post infusion < 5.0 micromol/L; 48 hrs post infusion <0.50 micromol/L; 72 hrs post infusion <0.10 micromol/L
Tube Type: Dark green top (Sodium Heparin)
Specimen: Blood
Alternate Specimen: Red top (no gel)
Pediatric Requirements: 1 dark green microtainer
Volume: 1 mL
Minimum Volume: 0.5 mL
Temperature: Refrigerated if not delivered to the lab immediately after collection.
Stability: Refrigerated: 2 days, frozen at -20 C for longer storage
Reasons for Rejection: Improper collection
Days Performed: Daily
Times Performed: Continuous
TAT: Stat: 1 hour, routine: 2 hours
Special Instructions: Send to the lab immediately at room temperature. Refrigerate specimen if it cannot be delivered to the lab immediately. This test should not be used in patients given Glucarpidase (Carboxypeptidase G2) rescue.
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