Macrocytosis in alcoholics is thought to be the result of direct toxicity of acetaldehyde, the by-product of ethanol metabolism on the bone marrow hematopoietic cells. As the life span of erythrocytes is 120 days in average, macrocytosis may persist on blood test results for up to 4 months after complete abstinence of alcohol drinking, i.e. until the old macrocytic red blood cells are cleared from the circulation.
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