What are the signs of iron deficiency?

Iron deficiency develops in stages. First the iron stores fall. Then less iron reaches the cells that make red blood cells, while hemoglobin is usually still normal. Last, hemoglobin drops and iron deficiency anemia appears.^[1] Anemia can cause weakness, tiredness, trouble concentrating and stomach or gut problems. It can also weaken immune function and body temperature control.^[1]

A blood ferritin level below 30 µg/L suggests iron deficiency, and below 10 µg/L suggests iron deficiency anemia. Inflammation, for example from an infection, can raise ferritin.^[1] Groups at higher risk include pregnant women, infants and young children, women with heavy periods, frequent blood donors, and people with cancer, gut disorders or heart failure.^[1] In men and in women after menopause, the usual causes are blood loss in the gut and poor absorption, so a doctor looks for the source.^[2]