This policy establishes Blue Cross Blue Shield of New Mexico (BCBSNM) laboratory reimbursement criteria for assessment of vitamin B12 status and for use of methylmalonic acid (MMA) testing. Serum vitamin B12 is the primary laboratory test used to evaluate clinical vitamin B12 deficiency. When serum B12 results are borderline or clinical suspicion persists despite a normal or low‑normal B12 level, MMA testing is recommended to confirm deficiency or further evaluate biochemical status. (See policy title and scope: "Vitamin B12 and Methylmalonic Acid Testing" and reimbursement criteria.)
Testing may be reimbursable when ordered for individuals being evaluated for clinical manifestations of vitamin B12 deficiency. The policy lists reimbursable clinical presentations that support testing, including cutaneous manifestations (for example, hyperpigmentation, jaundice, vitiligo); gastrointestinal manifestations such as glossitis; hematologic manifestations including macrocytic or megaloblastic anemia, leukopenia, pancytopenia, thrombocytopenia or thrombocytosis; and neuropsychiatric manifestations such as areflexia, cognitive impairment (including dementia‑like symptoms and acute psychosis), gait abnormalities, irritability, olfactory impairment, loss of proprioception and vibratory sense, and peripheral neuropathy.
The policy also describes risk‑based screening indications that may be reimbursable for asymptomatic individuals with one or more risk factors, including decreased ileal absorption (e.g., Crohn disease, ileal resection, tapeworm infection); decreased intrinsic factor (e.g., atrophic gastritis, pernicious anemia, post‑gastrectomy syndrome, and patients post‑bariatric surgery such as Roux‑en‑Y, sleeve gastrectomy, biliopancreatic diversion/duodenal switch); genetic causes (e.g., transcobalamin II deficiency); inadequate intake (e.g., alcohol abuse; age > 75 years or elderly individuals being evaluated for dementia; vegans or strict vegetarians, including exclusively breastfed infants of vegetarian/vegan mothers; eating disorders); and prolonged medication use (for example histamine H2 blocker or proton pump inhibitor use > 12 months, or metformin use > 4 months).
For individuals already receiving treatment for vitamin B12 deficiency, monitoring vitamin B12 testing may be reimbursable when performed no sooner than 3 months after initiation of therapy. Providers are expected to document clinical signs/symptoms that justify testing or the presence of listed risk factors when ordering screening tests, and to document therapy start dates when monitoring treated patients. BCBSNM notes that plan documents and product‑level coverage may vary, so providers should check specific plan documents for applicability to a given member.
The policy explicitly identifies tests and uses that are not reimbursable under the stated criteria: homocysteine testing is not reimbursable for confirmation of vitamin B12 deficiency; holotranscobalamin testing is not reimbursable for screening, testing, or confirmation of vitamin B12 deficiency; and screening for vitamin B12 deficiency in healthy, asymptomatic individuals is not reimbursable. Claims for these non‑reimbursable tests or uses are subject to denial under BCBSNM procedures.