- MCV usually very high (>110)
- May not have frank anemia
- If low, order Intrinsic Factor Antibody (IFA) to Dx Pernicious Anemia (PA)
- Order Methylmalonic Acid (MMA) & Homocysteine (HC)
- If MMA & HC are high, order IFA
- If low B12, or high MMA & HC, Dx PA even if IFA neg
- PA is common in elderly
- Gold standard Shilling Test no longer available
- Neuro sequelae (neuropathy, dementia) may be worse than anemia
- Neuro Sx can occur without anemia
- Tx: Vit. B12 shots 1 mg (1,000 mgm) IM, given daily x1 wk, then weekly x1 mo., then monthly forever
- Can also Tx oral B12, 1-2 mg per day forever, if adherence adequate
See posting Anemia – 3.