Test Directory

Home Test Search Results MTHFR (C677T) Mutation
MTHFR (C677T) Mutation

Justification

Individuals carrying the T allele have reduced MTHFR enzyme activity and hyperhomocysteinemia. Several studies in the past found an association between the T variant and several diseases (e.g., venous thrombosis); however, those follow-up studies failed to replicate the earlier findings or gave mixed results. This variant is very common in the population, with an allele frequency ranging from 7 to 39% depending on the population.

STAT: < 48 hours (M-F)

RT-PCR

Draw Tube: Purple Top

Sample Type: EDTA Whole Blood

DRAW KITS AVAILABLE

Specimen Requirements

Sample Type Volume Required Minimum Volume Stability
PREFERRED EDTA Whole Blood 3mL 1mL Room Temp.: 1 month
Refrigerated: 1 month
ALTERNATIVE Cheek swab 2 swab - Room Temp.: 1 month
Refrigerated: 1 month
REJECTION CRITERIA Sample contamination; sample compromised
SPECIAL INSTRUCTIONS -

General Information

METHODOLOGY RT-PCR
STAT TAT < 48 hours (M-F)
STAT TAT Performance > 90% of results released in 48 hours
ROUTINE TAT < 1 week
ALTERNATIVE NAMES c.665C>T, p.Ala222Val
DESCRIPTION This test detects the C677T variant (c.665C>T, p.Ala222Val) using real-time PCR. This test can detect whether a patient is normal or has one C677T allele (i.e., heterozygous) or two alleles (i.e., homozygous).
LIMITATIONS Rare variants within the primer binding sites could lead to allele drop-out and a potential false negative result. Rare, pathogenic variants in MTHFR can cause an autosomal recessive inborn error of metabolism with developmental delay, eye disorders, thrombosis and osteoporosis. To detect these variants, full gene sequencing should be ordered.
NORMAL RANGE No mutation found
ASSOCIATED TESTING -
REFERENCES

Hickey S.E., Curry C.J., Toriello H.V. ACMG Practice Guideline: lack of evidence for MTHFR polymorphism testing. Genet Med. 2013;15(2):153–6.
SAMPLE REPORT Upon request
NEW YORK STATE APPROVED No

Test Codes

ORDER CODE P3079
CPT CODE 81291
LOINC CODE 28005-7