| Methylenetetrahydrofolate Reductase (MTHFR) C677T and A1298C Variants (8000101256) | |
|---|---|
| Test Mnemonic: | MTHFR |
| Specimen Requirements: | |
| Collection: | Whole Blood |
| Container: | Lavender (EDTA), pink (K2EDTA), blue (Sodium Citrate), or yellow (ACD Solution A or B) color top tubes |
| Minimum Volume: | 1ml |
| Storage/Transport: | Ambient |
| Stability: | 5 days |
| Causes for Rejection: | Incorrect tube, inadequate volume |
| Reference Range: | Negative |
| Turnaround Time: | 3-7 days |
| Methodology: | GenMark eSensor |
| Performed: | Molecular Diagnostics Laboratory |
| Synonyms: | MTHFR, Methylenetetrahydrofolate Reductase, Hyperhomocysteinemia, pharmacogenetics of medications affecting folate metabolism |
| CPT 4 Code: | 81291 |
| Note: |
Phenotype Characteristics: MTHFR 665C>T and 1286A>C variants correlate with reduced enzyme activity; however, only homozygotes for the 665C>T variant have been associated with elevated plasma homocysteine levels and increased risk for premature cardiovascular disease. These individuals may also show toxicity from medications (i.e., methotrexate) that affect folate metabolism.
Incidence: The allele frequency of 665C>T is 0.35 in European Caucasians and 0.12 in African Americans. The allele frequency of 1286A>C is 0.31 in European Caucasians and 0.15 in African Americans. Mutation Tested: C677T (c.665C>T; p.Ala222Val) and A1298C (c.1286A>C; p.Glu429Ala). Methodology: Mutation is detected using genomic DNA, multiplex polymerase chain reaction, and eSensor XT-8 System. Assay uses U.S. Food and Drug Administration (FDA) approved kit (GenMark Diagnostics). Analytic Sensitivity and Specificity: 99 percent. Limitations: Diagnostic errors can occur due to rare sequence variations. Only the two MTHFR variants will be tested. Counseling and informed consent are recommended for genetic testing. References: OMIM: 607093 |
| When ordering tests for which Medicare or Medicaid reimbursement will be sought, physicians should only order tests that are medically necessary for the diagnosis or treatment of the patient. Components of the organ or disease panels may be ordered individually. The diagnostic information must substantiate all tests ordered and must be in the form of an ICD-10 code or its verbal equivalent. | |