Hi Kate,
Low ferritin, low serum iron, very low iron saturation and high TIBC all point to iron deficient anemia. The high RDW is possibly related to your ongoing blood loss, although it can also be the result of alpha minor. The possibility of alpha minor does cloud some of the readings, but the iron levels all point to iron deficiency. I have to say that possible blood loss is my main concern here. The lack of response to iron could signal a continued blood loss and this has to be regularly monitored until you are certain there are no more polyps and no more bleeding. I have been extremely iron deficient due to blood loss after surgery. I could not take iron and had to correct the deficiency on a vegetarian diet. Even then, within six months, I was well on my way to normalcy. I would have to say that either the form of iron you are using doesn't work for you, or there is still some bleeding. A hematologist may have some ideas for correcting the iron problem and also some insight into why nothing has changed.