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Laboratory Test Directory

MTHFR Polymorphism Analysis (C677T & A1298C)


Name Method Department Units
MTHFR Polymorphism Analysis (C677T & A1298C) Polymerase chain reaction (PCR)
DNA extraction
Molecular Genetics

Specimen Requirements

Whole blood

Container Type Container Size Specimen Volume

Purple tube (EDTA)

3 mL 3 mL

Room temperature - 24 hour(s)
Refrigerated - 72 hour(s)

Specimen Preparation

  • Do not centrifuge
  • Do not freeze

Reasons for Rejection

  • Wrong collection tube
  • Clotted specimen
  • Frozen specimen
  • Centrifuged specimen


Please click on the Lab Form Link in the Forms Section to print and complete the Genetic Test Requisition Form. Submission of completed Genetic Test Requisition Form is required, and submission of informed consent form is recommended.

This assay evaluates for two common variants, c.665C>T and c.1286A>C (also known as C677T and A1286T), in the MTHFR gene. These two variants in the MTHFR gene correlate with reduced MTHFR enzyme activity; however, only homozygotes for the c.665C>T variant have been?associated with elevated plasma homocysteine levels (hyperhomocysteinemia). These individuals may also show toxicity from medications (i.e., methotrexate) that affect folate metabolism.??

Please Note:??Targeted mutation analysis for these two polymorphic variants in the MTHFR gene is frequently ordered as part of the clinical evaluation for thrombophilia. It has been disproven that reduced MTHFR enzyme activity ultimately led to an increased risk for venous thromboembolism, coronary heart disease and recurrent pregnancy loss. Current guidelines by the American College of Medical Genetics (PMID: 23288205), American Academy of Family Physicians ( and the American College of Obstetrics and Gynecology (PMID: 23963422) do not endorse testing for MTHFR polymorphisms for routine risk assessment or in specific settings, including evaluation of thrombosis risk or recurrent pregnancy loss. Data available to suggest genetic testing for MTHFR polymorphisms for diagnosis or management of all other indications, including but not limited to, depression, coronary artery disease, cancer, congenital heart defects, Alzheimer?s, dementia, hepatitis, stroke, infertility, Parkinson?s, migraines, peripheral neuropathy, diabetic retinopathy, autism spectrum disorder, nitrous oxide use, schizophrenia and vascular disease is weak, inconsistent, biased, and inconclusive.

If ordered with Factor 2 and/or Factor 5 Mutation Analyses (test code: F52MUT), all ordered tests can be performed on the same EDTA blood sample. It is NOT necessary to collect additional tube for each additional gene analysis.


Lab Form

CPT Code

  • 81291 (x2)