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Diagnostic Services

Genetics Lab


Methylene Tetrahydrofolate Reductase (MTHFR) Mutation Analysis

Methylene tetrahydrofolate reductase is an enzyme involved directly, and indirectly, in folate and homocysteine metabolism. The (thermolabile) c.677C>T MTHFR polymorphism is present in the homozygous form in 5-15% of the general population. Individuals who are homozygous for the c.677C>T MTHFR variant may have mild elevations in blood homocysteine levels, especially in the setting of inadequate folate intake. Elevated homocysteine is an independent risk factor for venous thromboembolism. Approximately 20% of the population are compound heterozygotes for both MTHFR polymorphisms. Less is known about the thrombotic risk associated with 1298 A>C. The presence of other predisposing risk factors for thrombosis in addition to elevated homocysteine is considered synergistic. The c.677C>T variant is also associated with methotrexate toxicity.

Test Name: Methylene Tetrahydrofolate Reductase, (677C>T, 1298A>C)
Test Code:
Test Description:
Analysis of the MTHFR gene for the following variants:
MTHFR; coagulation; thrombosis
This test is indicated for:
-Individuals with family history of MTHFR thermolabile mutation
-individuals with history of venous thromboembolism as part of thrombophilia work up
-individuals receiving methotrexate chemotherapy treatment
Related Tests: Factor V Leiden (p.R506Q)  
Analysis of the Factor V gene for the Leiden (R506Q) mutation.

Prothrombin variant (Factor II), mutation analysis (20210G>A)  
Analysis of the F2 gene for the 20210G>A mutation.

Thrombosis Risk Panel  

Clinical Links:
Available weekly
Turnaround Time:
1 week
Reference Range:
Interpretive report provided
Consent Form:
Sample Requirements: Type
Blood: 1-3 ml EDTA (purple) tube.
DNA: 5ug extracted DNA

Refrigerate blood samples which will not be immediately shipped.

Ship overnight at room temperature.
Samples Received:
Mon - Fri 8:00am - 5:00pm PST
Special Considerations:
Note that this test can be ordered individually or as part of a thrombosis risk panel that includes factor V Leiden, and the prothrombin 20210G>A mutations.
Please e-mail Lab Client Services ( or call at 206-987-2617 with any billing questions
CPT Code:
Please e-mail Lab Client Services ( or call at 206-987-2617 with any billing questions