Büşra DEMİRCİ, Gülşah EFEOĞLU GÜLSOY, Sevinç Püren YÜCEL, Fatma Burçin KURTİPEK, Eda ÖZAYDIN
Archives of Current Medical Research - 2026;7(3):592-599
Background: Folate and vitamin B12 interact in one-carbon metabolism, and imbalance between them may influence hematological findings. Although high folate status may mask vitamin B12 deficiency in adults, evidence in infants is limited. This study evaluated the association between folate status and hematological parameters in infants with vitamin B12 deficiency. Methods: This retrospective cross-sectional study included infants aged 0-24 months with serum vitamin B12 levels <200 pg/mL and simultaneous complete blood count and folate measurements between 2020 and 2025. Infants with iron deficiency or chronic inflammatory conditions were excluded. Participants were categorized according to serum folate levels (<20 ng/mL vs. >=20 ng/mL), and hematological parameters were compared. Results: A total of 197 infants were included. Hemoglobin levels did not differ between folate groups. Infants with folate levels >=20 ng/mL had significantly lower mean corpuscular volume and higher red cell distribution width than those with lower folate levels. Conversely, neutrophil count and neutrophil-to-lymphocyte ratio were higher in the low-folate group. Other hematological parameters were comparable. Homocysteine levels, available in a limited subset, did not differ by folate status. Conclusions: Folate status was associated with distinct hematological patterns in infants with vitamin B12 deficiency despite similar hemoglobin levels. Higher folate levels were associated with lower mean corpuscular volume and increased red cell distribution width, suggesting possible masking of macrocytosis. Evaluation of red blood cell indices beyond hemoglobin may improve recognition of vitamin B12 deficiency in infancy.
