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HelpTest Code MTREX Methotrexate
Additional Codes
| Hospital Ordering Code |
|---|
| LAB481 Methotrexate level |
NOTE:
Specimens from patients who have received carboxypeptidase can contain a hydrolysis fragment of MTX (DAMPA) that cross-reacts with the methotrexate antibody used in this immunoassay.
Because enzyme immunoassay interference can result in overestimation of serum MTX concentrations immediately after administration of carboxypeptidase enzyme treatment (glucarpidase), it may be helpful to measure MTX after the glucarpidase dosing using a more specific assay (e.g. LC-MS/MS). The LC-MS/MS testing for MTX in these cases can be obtained by sendout to Mayo Medical Laboratories for "Methotrexate Post Glucarpidase, Serum."
Specimen Requirements
Preferred Collection Container:
Green NO Gel (Lithium Heparin)
Also Acceptable Collection Container:
Red (No Additive)
Collection Information:
Do not use gel separator tubes. Collect blood in a green no gel lithium heparin tube or serum red top tube.
Transport Information:
Centrifuge and aliquot 0.6 plasma or serum into a transport tube.
Minimum Sample Volume:
0.2 mL plasma or serum (approximately 0.4 mL of whole blood based upon a normal patient hematocrit)
Performing Laboratory
Pathology Laboratory, UnityPoint Health, Des Moines
SEND OUTS- This test is forwarded from PL to Methodist. Be sure to batch seperately, and label "TO IMMC STAT."
CPT
80204
Methodology
Immunoassay
Specimen Transport Temperature
Refrigerated Stability:
3 days
Frozen Stability:
6 months
Ambient Stability:
12 hours
Performance
Daily
24 hours a day
Analytical Time:
2 hours
Testing Laboratory:
Iowa Methodist Medical Center
Laboratory Section:
Core Laboratory