The MTHFR genetic test looks for common inherited variations (mutations) in the MTHFR gene, most often the C677T and A1298C variants. The MTHFR gene provides instructions for making an enzyme that helps the body process folate and convert homocysteine, an amino acid, into other useful substances. Certain variants can reduce how well this enzyme works. The test is used to identify whether a person carries one or both of the common MTHFR variants. It is sometimes ordered when a person has elevated homocysteine levels or a family history of certain conditions. Its clinical usefulness is debated, and many medical organizations no longer recommend routine MTHFR testing for most people.