Along the same thought line as Jan-could your body's inability to hold on to the iron that you are receiving actually be that your body is using it up to produce more red blood cells? A quick way of calculating how much iron you need to receive is 200 mg per 1 point of Hemoglobin increase, plus an additional 500 mg to replenish iron stores. If your hemoglobin is 8 and the doctor wants you at 12, then you need 1300 mg of iron to get you there. If you are only getting an infusion every couple of weeks, you may not be getting enough iron to adequately support RBC production. Kind of like going on a 500 mile trip, and only filling the gas tank half way. You didn't mention what type of physicians have been treating you. Hopefully, you are seeing a Hematologist. They would be the best medical specialist to get to the root cause of your problem.