RESUMO
BACKGROUND: The aim of this study was to determine the hematological status of severe vitamin B12 deficiency in infants and adolescents. METHODS: This study involved 95 infants and 117 adolescents with severe plasma vitamin B12 deficiency (< 120 pg/ mL) and normal plasma folate and ferritin. Infants were aged between one and 24 months. Adolescents were aged between 11 and 17 years. RESULTS: Macrocytic anemia was associated with nine (9.5%) out of 95 infants with severe vitamin B12 deficiency. Neutropenia was found in 16 (16.8%) out of 95 infants with severe vitamin B12 deficiency. Thrombocytopenia was not found in 95 infants with severe vitamin B12 deficiency. Macrocytic anemia was found in two (1.7%) out of 117 adolescents with a severe vitamin B12 deficiency. Neutropenia was associated in one (0.8%) out of 117 adolescents with severe vitamin B12 deficiency. Thrombocytopenia was not found in 117 adolescents with severe vitamin B12 deficiency. CONCLUSIONS: Low clinical or hematological findings for B12 deficiency in infants and adolescents living in regions at risk, such as those with low consumption of meat and other animal products warrant the measurement of vitamin B12 level.