In iron deficiency anemia, how soon does reticulocytosis typically begin after starting iron therapy?

• A. Within 7 days
• B. Within 2 weeks
• C. Within 1 month
• D. Immediately within 24 hours

Answer: (A)

When iron becomes available again, the bone marrow can restart producing red blood cells, and you’ll see this as reticulocytosis in the peripheral blood. The earliest reticulocytes appear after several days of therapy, with the typical onset around a week. This early rise reflects successful iron delivery allowing erythropoiesis to resume; the reticulocyte count often climbs within 3–7 days and peaks over the next week or two, while hemoglobin may take a bit longer to rise. If there’s no increase in reticulocytes by about a week, consider issues like nonadherence, malabsorption, ongoing blood loss, or other causes of anemia.