Dr. Roach: Source of low iron must be investigated
Dear Dr. Roach: I am a healthy, energetic 63-year-old woman who has had elevated RDW levels for the past few years. My doctor and I looked into this condition, and did a ferritin panel.
The test reports that, although my B-12, folic acid, hemoglobin and hematocrit are normal, my transferrin saturation is low, at 6 percent, and my iron and ferritin also are slightly low. I give blood regularly, but I am ceasing to do that for the time being.
What are some causes of my kind of anemia, where the red blood cell looks pale and undersized?
We are treating this with iron supplementation and will retest in three months, but I’m eager for any information that may be able to help me correct my numbers.
Dear S.C.: You have low iron, low ferritin and very low transferrin saturation (transferrin is a protein that moves iron around in the body, and a low “saturation” means that very little iron is attached to the transferrin) — all of which are consistent with an iron-deficiency anemia. On a blood smear, the cells, indeed, look pale and small.
“RDW” means “red cell distribution width,” and a high number means that the cells in the blood are of many different sizes.
This happens with iron deficiency, but it is very pronounced when there are two problems going on at the same time; for example, iron deficiency and vitamin B-12 or folic acid deficiency.
However, your B-12 and folic acid levels are normal, and your RDW could be explained by iron deficiency alone.
Giving blood regularly certainly could explain iron deficiency, especially if you don’t take in a lot of iron from your diet. (Vitamin C, by the way, in food or as a supplement, greatly enhances your body’s ability to absorb iron.)
However, every time I see iron deficiency in a man or a post-menopausal woman, I ask myself whether this could be colon cancer or another form of GI blood loss.
I recently have written some columns on people diagnosed with colon cancer despite a recent normal colonoscopy. Iron deficiency is a big red flag that considering a follow-up colonoscopy is wise if the previous colonoscopy was not both a good, complete prep and very recent.
A few weeks or months of iron should bring you back to normal, and if it doesn’t when you get retested, then I would definitely recommend that you look for a source of iron loss.
Email questions to ToYourGoodHealth@med.cornell.edu.