ARUP's Laboratory Test Directory

Methylenetetrahydrofolate Reductase (MTHFR) 2 Mutations : 0055655
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Patient History For Molecular Genetic Testing
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Additional Technical Information


Mnemonic: MTHFR PCR

Ordering Recommendation: Do not use for neural tube defect risk assessment or for thrombophilia screening. Use to determine genetic cause for hyperhomocysteinemia.
Methodology: Polymerase Chain Reaction/Fluorescence Monitoring
Performed: Sun-Sat
Reported: 2-7 days
Specimen Required: Collect: Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation: Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature: Refrigerated.

Stability (collection to initiation of testing): Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Reference Interval:
Negative: Neither of the common MTHFR gene mutations tested, C677T and A1298C, were detected. Other causes of elevated homocysteine levels, coronary heart disease, or thrombosis cannot be excluded. This genotype is associated with a normal folate metabolism.
Interpretive Data: Background Information for Methylenetetrahydrofolate Reductase (MTHFR) 2 Mutations:
Characteristics: Mutations in the MTHFR gene (C677T and A1298C) correlate with reduced enzyme activity; however, only homozygotes for C677T or compound heterozygotes for C677T/A1298C have significantly elevated plasma homocysteine levels and increased risk for premature cardiovascular disease. These individuals may also show toxicity from medications (ie, methotrexate) that affect folate metabolism.
Incidence: US allele frequency of C677T = 0.39 and A1298C = 0.17; homozygosity for C677T is 1-15 percent.
Inheritance: Autosomal recessive.
Cause: Homozygosity for MTHFR gene mutation C677T or compound heterozygosity for C677T/A1298C.
Mutations Tested: c.677C>T and c.1298A>C.
Clinical Sensitivity: Undefined. Sensitivity is dependent upon multiple contributing factors.
Methodology: PCR followed by fluorescent monitoring using hybridization probes.
Analytical Sensitivity & Specificity: 99 percent.
Limitations: Only the two MTHFR gene mutations (C677T and A1298C) will be targeted; rare diagnostic errors may occur due to primer site mutations.

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.



Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.

See Compliance Statement C: www.aruplab.com/CS
CPT Code(s): 81291
Cross References: Hyperhomocystinemia, C677T and A1298C Mutations (Methylenetetrahydrofolate Reductase (MTHFR) 2 Mutations) , MTHFR (Methylenetetrahydrofolate Reductase (MTHFR) 2 Mutations)