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Test Code:
090-30-2620

Order Name:
Methotrexate (Blood)

 
Useful For:
  • Determination of methotrexate in human serum.
  • Used in monitoring levels of methotrexate to ensure appropriate therapy.
 
Methodology:
Chemiluminescent Microparticle Immuno Assay (CMIA)
 
AliasesName:
MTX (Methotrexate), Blood
 
 
 
Test Code:
090-30-2620

Order Name:
Methotrexate (Blood)

 
Collection Specimen Or Container:
Blood/ Plain Blood (Red Top) 6 mL, 1 tube
 
Specimen Testing Type:
Serum, minimum volume 1 mL
 
Sub Mission Container:
Plastic vial
 
Rejection Criteria:
Hemolysis: 4+ reject
 
Specimen Stabillity:
Specimen Type Temperature Time
Serum (keep in original tube) Refrigerated, 2oC to 8oC 8 hours
Serum Refrigerated, 2oC to 8oC 2 days
Frozen, -20oC 14 days
 
 
 
Test Code:
090-30-2620

Order Name:
Methotrexate (Blood)

 
Method detail:
Chemiluminescent Microparticle Immuno Assay (CMIA)
 
Schedule:
Tested Daily (24 Hours)
 
Turnaround Time:
Specimen collected to reported within 4:00 Hours
 
Performing Location:
Immunology, Laboratory Department Tel. 13227
 
Specimen Retention Time:
5 days
 
 
 
Test Code:
090-30-2620

Order Name:
Methotrexate (Blood)

 
 
Clinical Information:
Methotrexate (MTX, amethopterin) is a folate antimetabolite. It is an analog of aminopterin, which is also derived from folic acid. The molecular structure of methotrexate differs from folic acid in that it has a hydroxyl
group in place of the 4-amino group on the pteridine ring and there is no methyl group at the N position.
Methotrexate is an antineoplastic drug used solely or in combination with other antineoplastic drugs for the treatment of leukemia and other diseases. Relatively low doses of methotrexate have been used in the treatment of nonmalignant diseases such as severe psoriasis, asthma, rheumatoid arthritis, sarcoidosis, and transplantation therapy.

Intermediate to high doses of methotrexate with Leucovorin rescue have been used with favorable results in the treatment of osteogenic sarcoma, leukemia, non-Hodgkin’s lymphoma, lung and breast cancer. Methotrexate levels are monitored to avoid excessive toxic effects of the drug and to determine when to intervene with counter-acting ‘rescue’ therapy. Adverse reactions include myelosuppression, stomatitis, nausea,
vomiting, convulsions, liver and renal abnormalities, anemia, leukopenia, thrombocytopenia, osteoporosis, neurotoxicity, and leukoencephalopathy.

There are no current indications for monitoring low dose methotrexate therapies.
 
Reference Value:
Increased risk of toxicity.
  • Methotrexate >10 umol/L 24 hours after dose.
  • Methotrexate >1 umol/L 48 hours after dose.
  • Methotrexate >0.1 umol/L 72 hours after dose.
 
Clinical Reference:
  1. Manufacturer’s reagent package insert, Architect® Methotrexate, ABBOTT Max-Planck-Ring 2 65205 Wiesbaden Germany, December 2014
  2. ​Reference intervals: UpToDate. Waltham, MA: UpToDate Inc. http://www.uptodate.com (Retrieved: July 2018)