4 yo has a slightly low hgb. it is 11.2. his hct is normal. should i be concerned there is an underlying problem other than iron deficiency?

Iron deficiency: In pediatrics we are taught the first 3 causes of anemia are "iron deficiency, iron deficiency, iron deficiency". Typically you treat for iron deficiency, and pt takes 3 months of supplemental iron and then you recheck hgb and hematocrit to see if it corrected. If it did not and pt actually took the iron as directed then you would look for a different cause.