Vitamin B12 and folate deficiency: should we use a different cutoff value for hematologic disorders?

Summary Introduction Anemia and macrocytosis are well‐defined expected hematologic findings of vitamin B 12 and folate deficiency; however, some previous studies did not show a significant association of subnormal B 12 with anemia and macrocytosis. Methods We retrospectively analyzed 17 713 laboratory patient records to evaluate vitamin B 12 and folate levels in relation to anemia and macrocytosis. Results In an age‐ and sex‐adjusted logistic regression model, low B 12 status but not marginal B 12 status was significantly associated with anemia [ OR s respectively, 1.291 (95% CI , 1.182–1.410), 1.022 (95% CI , 0.943–1.108)] and macrocytosis [ OR s, respectively, 3.853 (95% CI , 3.121–4.756), 1.031 (95% CI , 0.770–1.381)]. Also low folate status but not marginal folate status was significantly associated with anemia [adjusted OR s, respectively, 1.819 (95% CI , 1.372–2.411), 1.101 (95% CI , 0.931–1.301)] and macrocytosis [adjusted OR s, respectively, 2.945 (95% CI , 1.747–4.965), 1.228 (95% CI , 0.795–1.898)]. Conclusion Our results show that increased anemia and macrocytosis are observed at values below commonly used B 12 lower‐reference thresholds. Determining a hematologic cutoff value may help physicians in clinical practice.