Absolutely! A significant number of patients with B-12 deficiency are neither anemic nor have macrocytosis but may still have related neurological symptoms.
A large study involving a nationally representative sample of older U.S. adults (aged >50 y) sponsored by the CDC reported a prevalence of B-12 deficiency without anemia or without macrocytosis of about 4% each . 1 Interestingly, in this study, there was no evidence that mandatory folic acid fortification of certain foods was associated with lower prevalence of B-12 deficiency without anemia or macrocytosis.
In another study, the proportion of subjects with low serum B-12 but without macrocytosis was 70% or higher, irrespective of pre- or post-fortification period.2 Interestingly, in the age group <65 y, the post-fortification was associated with significantly higher proportion of patients without macrocytosis (85% vs. 45% in the prefortification period) in this study.
Younger age groups seem to also be overrepresented among patients with B-12 deficiency but no anemia, with a prevalence of 50% in <60 y age group with B-12 deficiency compared to 38% and 31% among older age groups (60-74 y and >74 y, respectively).3
So, keep B-12 deficiency in mind in the presence of compatible neurological symptoms even in the absence anemia or macrocytosis!
- Qi YP, Do AN, Hamner HC, et al. The prevalence of low serum vitamin B-12 status in the absence of anemia or macrocytosis did not increase among older U.S. adults after mandatory folic acid fortification. J Nutr 2014;144:170-76. http://jn.nutrition.org/content/144/2/170.abstract
- Wyckoff KF, Ganji V. Proportion of individuals with low serum vitamin B-12 concentrations without macrocytosis is higher in the post-folic acid fortification period than in the pre-folic acid fortification period. Am J Clin Nutr 2007;86:1187-92. https://www.ncbi.nlm.nih.gov/pubmed/17921401
- Mills JL, Von Kohorn I, Conley MR, et al. Low vitamin B-12 concentrations in patients without anemia: the effect of folic acid fortification of grain. Am J Clin Nutr 2003;77:1474-7. http://ajcn.nutrition.org/content/77/6/1474.full.pdf+html