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Test Code LABMTH2 Methylenetetrahydrofolate Reductase (MTHFR) 2 Variants

Additional Codes

Test Name in Epic EPIC Test Code Mnemonic ARUP Test ID
MTHFR 2 MUTATIONS ANALYSIS, B LABMTH2 MTHFR PCR 0055655

 

Methodology

Polymerase Chain Reaction/Fluorescence Monitoring

Specimen Requirements

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.

Unacceptable Conditions

Plasma or serum. Heparinized specimens. Frozen specimens in glass collection tubes.

Day(s) Test Set Up

Sunday-Saturday

Reported 2-6 days

Performing Laboratory

ARUP Laboratories

Test Classification and CPT Coding

CPT:  81291

Component Test Code*      Component Chart Name                       LOINC
0055657                              MTHFR Mutation: c.665C>T                 28005-7
0055658                              MTHFR Mutation: c.1286A>C               28060-2
0055660                              MTHFR Interpretation                            21709-1
2001331                              MTHFR PCR Specimen                        31208-2
 

Specimen Stability Information

Stability
Ambient: 72 hours; Refrigerated: 1 week; Frozen: 1 month

Interpretive Data

Background Information for Methylenetetrahydrofolate Reductase (MTHFR), 2 Variants:
Characteristics: Variants in the MTHFR gene may reduce enzyme activity contributing to hyperhomocysteinemia. Although hyperhomocysteinemia was previously reported to be a risk factor for many conditions, especially venous thrombosis and cardiovascular disease, recent meta-analysis casts doubt on whether lifelong moderate homocysteine elevation has an effect on cardiovascular disease. The American College of Medical Genetics Practice Guidelines indicate that individuals with elevated homocysteine and two copies of the c.665C>T variant have an odds ratio of 1.27 for venous thromboembolism. Thus, they recommend MTHFR genotyping not be ordered as part of a routine evaluation for recurrent pregnancy loss or thrombophilia due to questionable clinical significance.
Incidence: The allele frequency of the c.665C>T variant is 0.35 in European Caucasians, 0.5 in Hispanics, and 0.12 in African Americans.
Inheritance: Autosomal recessive; two copies of the c.665C>T variant may be a contributing factor to hyperhomocysteinemia.
Variants Tested: c.665C>T(p.Ala222Val) and c.1286A>C(p.Glu429Ala). (legacy names, C677T and A1298C, respectively).
Clinical Sensitivity: Undefined; hyperhomocysteinemia is caused by genetic, physiologic and environmental factors. MTHFR variants are only one contributing factor.
Methodology: Polymerase chain reaction (PCR) and fluorescence monitoring.
Analytical Sensitivity & Specificity: 99 percent.
Limitations: Only two MTHFR gene variants (c.665C>T and c.1286A>C) are tested. Diagnostic errors can occur due to rare sequence variations.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.


Compliance Category
Laboratory Developed Test (LDT)