Be careful with presuming that low ferritin means low iron. They are not the same thing. For example, some people have very low ferritin and low serum iron, but super high liver iron (though this is a rare genetic disorder). Ferritin and iron do not always match. I have super high ferritin and lowish iron - technically "normal" but if my iron drops even one point it wont be. Ferritin is just a clue something might be going on with iron, but then you need further iron tests to be sure.