| Test Name: |
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Methotrexate
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| Test Code(s): |
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MTX / HCMTX
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| CPT Code(s): |
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80299
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| Methodology: |
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Immunoassay
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| Clinical Significance: |
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Antineoplastic
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| Days Performed: |
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Daily, dayshift- Pathology Resident approval is required after hours.
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| Turnaround Time: |
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Stat: 2 hours.
Routine: 24 hours.
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Specimen Requirements
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| Specimen: |
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Blood
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| Collection Container: |
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Preferred: Red top
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| Collection Volume: |
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Preferred: 3 mL
Pediatrics: 1 mL
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| Sample Analyzed: |
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Serum
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| Volume Required: |
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Preferred: 1 mL
Pediatrics: 0.3 mL
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| Specimen Processing: |
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Centrifuge. Transfer cell-free serum to plastic vial. Refrigerate.
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| Specimen Transport: |
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Transport specimen to UWHC Core Laboratory (B4/220). Transport with coolant pack if coming from outreach location.
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| Unacceptable Criteria: |
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Specimens collected in red cap with yellow ring (SST) tubes are not acceptable.
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Interpretation
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The laboratory does not interpret methotrexate levels.
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| Additional Information: |
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Result of "BELOW" indicates that the result is below the method detection limit of 0.07 umol/L. Dependent on test results as applied to dose and interval, adjustments may need to be made in the leucovorin rescue dose, interval, and/or duration. Levels and rescue should be continued on a 24 hour basis until methotrexate level is less than 0.1 umol/L.
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