Hyperhomocysteinemia Genotyping for Thrombotic Risk Assessment

Homocysteine genotyping, MTHFR genotyping, Hyperhomocysteinemia genotyping, Hyperhomocysteinemia (MTHFR) Genotyping , EPIC: LAB6386, SOFT: MTHG


This test is available to outpatients only. For questions, please call 800-551-0488.

Specimen Collection Criteria

Collect: One 10 mL whole blood in Lavender-top EDTA tube. (Min: 5.0 mL)

Physician Office/Drawsite Specimen Preparation

Do not freeze specimens. Maintain whole blood at room temperature (20-26°C or 68-78.8°F) prior to transport.

Preparation for Courier Transport

Transport: Whole blood at room temperature (20-26°C or 68-78.8°F). (Min: 5.0 mL whole blood)

Rejection Criteria

  • Frozen specimens. 
  • Unlabeled tubes. 
  • Specimens collected in heparin (Green-top), clot tubes (Red-top), or SST tubes.
  • This test will only be performed once in a lifetime for a patient.


Specimens are stable at room temperature up to 72 hours.


Once per week.
Results available in 7-10 business days.

Reference Range

Negative (no mutation).

Test Methodology

InvaderTM technology using Cleavase Enzyme followed by FRET Detection.


Hyperhomocysteinemia may be due to inherited mutation in the MTHFR gene, or may be secondary to folic acid and/or vitamin B12 deficiency. Patients homozygous for the C677T mutation have a 60 - 65% reduction in MTHFR activity and twice the plasma homocysteine concentration compared to normal individuals with no mutation. A second MTHFR gene mutation, A1298C is significant in cases of compound homozygosity with the C677T mutation.

Clinical Utility

  • The MTHFR mutations result in elevated plasma homocysteine levels which are a strong and independent risk factor for occlusive vascular disease.
  • Testing for MTHFR Genotyping is recommended for:
    • Patients with elevated total plasma homocysteine levels.
    • Patients with positive family history of arterial thrombosis.
    • Patients with documented atherosclerotic (coronary artery, cerebrovascular, or periperal vascular) disease.
  • Plasma homocysteine levels may be normalized by nutritional supplements of folic acid and vitamin B12.

CPT Code


Test Codes


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