Laboratory study results revealed additional abnormalities. This included a macrocytic anemia and neutropenia. Her hemoglobin level was 9.4 g/dL (normal range, 12.0-15.5 g/dL), her mean corpuscular volume was 113.8 fL (normal range, 81.6-98.3 fL), and her neutrophil count was 1020/mm3 (normal range, 1700-7000/mm3). The folate level and the findings from the iron studies were normal. Her serum vitamin B12 level was 631 pg/mL (466 pmol/L) (normal range, 200-650 pg/mL [148-480 pmol/L]) with a methylmalonic acid level of 0.18 µmol/L (normal level, <0.4 µmol/L) and a serum homocysteine level of 13 µmol/L (normal level, <13 µmol/L). Her serum urea nitrogen value was elevated to 59 mg/dL (21.1 mmol/L) (normal range, 6-21 mg/dL [2.1-7.5 mmol/L]), and her creatinine level was normal. Her total protein level was decreased to 5.4 g/dL (normal range, 6.3-7.9 g/dL), and her alkaline phosphatase level was elevated to 423 U/L (normal range, 119-309 U/L) with normal alanine aminotransferase and aspartate aminotransferase levels. The findings from the lipid profile, immunoelectrophoresis, thyroxine test, antinuclear antibody test, paraneoplastic panel, vitamin E level test, and the fatty acid profile were normal. Findings for Lyme disease titers, syphilis, human T-lymphotrophic virus 1, and hepatitis B and C serologies were also normal. The lumbosacral spine magnetic resonance imaging results showed incidental degenerative changes. No signal change was present in the lateral or dorsal columns. The nerve conduction studies were remarkable for an axonal sensorimotor polyneuropathy based on an absent sural sensory potential with slight reduction in the peroneal and tibial motor amplitude with normal lower limb motor-conduction velocities.