Reference Interval:
By report
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| Interpretive Data: |
Background Information: The C677T and the A1298C mutations in the methylenetetrahydrofolate reductase (MTHFR) gene correlate with reduced enzyme activity; however, only individuals homozygous for the C677T mutation or compound heterozygous for the C677T/A1298C mutations have significantly elevated plasma homocysteine levels. Homozygosity for the C677T mutation is associated with methotrexate-related toxicity. Homozygosity for the A1298C mutation is associated with lower methotrexate dose requirements.
Methodology: Patient DNA is assayed for the C677T and the A1298C mutations in the MTHFR gene by polymerase chain reaction (PCR) and fluorescence monitoring using hybridization probes.
Limitations: Mutations in other genes or mutations other than C677T and A1298C in the MTHFR gene may affect toxicity and efficacy of methotrexate.
Analytical Sensitivity/Specificity: 99.9%
This test is performed pursuant to an agreement with Roche Molecular Systems, Inc.
This test is performed pursuant to an agreement with Siemens Medical Solutions.
Please refer to Statement C in the Compliance Statements section in the front of the Laboratory Test Directory.
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| Note: |
For homocysteine levels by MTHFR genotyping, refer to test Methylenetetrahydrofolate Reductase Mutation Detection (Thermolabile Form) (C677T & A1298C) (0055655).
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| CPT Code(s): |
83890 Isolation; 83900 Molecular diagnostics; 83896 x4 Nucleic acid probe; 83912 Interpretation and report - Additional CPT code modifiers may be required for procedures performed to test for oncologic or inherited disorders.
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