Ob-Gyn Coding Alert

Question: What is MTHFR, and what codes should I report for it?

Alabama Subscriber

Answer: MTHFR (Methylene-tetra-hydro-folate-reductase) is an enzyme that is needed to metabolize homocysteine, an amino acid found in protein foods.

When the mother carries a genetic mutation (MTHFR) that inhibits the production of this enzyme, this can affect either her or the fetus. When homocysteine levels are elevated (because MTHFR is lacking), she will have an increased risk of fetal neural tube defects and miscarriage. An elevated homocysteine level can also indicate an increased risk factor for blood clots, arteriosclerosis and strokes in the mother.

Because she is pregnant, you would have to either assign O99.28 (Other endocrine, nutritional and metabolic diseases complicating pregnancy, childbirth and the puerperium) as the primary diagnosis or if she was showing signs of hypercoagulation problems, you should code O99.11- (Other diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism complicating pregnancy) with a sixth digit of 1, 2 or 3 to indicate the trimester.

She may also have a history of recurrent fetal loss, stillbirth, or neural tube defects. So reporting a O09 high risk category code is also an option if she is not currently showing signs of the condition herself. The non-ob code for this condition is E72.12 (Methylenetetrahydrofolate reductase deficiency).