Current hematological findings in cobalamin deficiency. A study of 201 consecutive patients with documented cobalamin deficiency

Summary With the introduction of automated assays for measuring serum cobalamin levels over the last decades, the hematological manifestations related to cobalamin deficiency have been changed from the description reported in ‘old’ studies or textbooks. We studied the hematological manifestations or abnormalities in 201 patients (median age: 67 ± 6 years) with well‐documented cobalamin deficiency (mean serum vitamin B12 levels 125 ± 47 pg/ml) extracted from an observational cohort study (1995–2003). Assessment included clinical features, blood count and morphological review. Hematological abnormalities were reported in at least two‐third of the patients: anemia (37%), leukopenia (13.9%), thrombopenia (9.9%), macrocytosis (54%) and hypegmented neutrophils (32%). The mean hemoglobin level was 10.3 ± 0.4 g/dl and the mean erythrocyte cell volume 98.9 ± 25.6 fl. Approximately 10% of the patients have life‐threatening hematological manifestations with documented symptomatic pancytopenia (5%), ‘pseudo’ thrombotic microangiopathy (Moschkowitz; 2.5%), severe anemia (defined as Hb levels