Iron deficiency can develop gradually, with the body’s stored iron being depleted before there is a measurable fall in haemoglobin. So, a normal haemoglobin level does not always mean that the body has adequate iron stores.
Ferritin is one of the key markers used to assess these iron stores. Gopinathan M., consultant, haemato-oncology (BMT), MGM Cancer Institute, compares ferritin to a warehouse where iron is stored for use whenever the body needs it. Iron is stored mainly in tissues such as the liver and spleen and within cells called macrophages. It is subsequently mobilised for erythropoiesis, the process through which red blood cells and haemoglobin are produced. Inflammation is particularly important. Ferritin is also an acute-phase reactant, meaning its level can rise during infection or inflammation. This can make iron stores appear better than they actually are. The World Health Organization recommends taking inflammation into account when interpreting ferritin and, where appropriate, using markers such as C-reactive protein alongside it. Treating the deficiency without addressing its cause can allow the problem to recur. Treatment commonly continues for several months, including after haemoglobin improves, to replenish iron stores, but the dose and duration depend on the cause and severity of the deficiency. The widespread availability of iron supplements can make self-treatment tempting, particularly when symptoms such as fatigue or hair loss are attributed to low iron. Dr.
Because a report shows a low ferritin, experts caution against starting iron tablets simply. Because the haemoglobin is normal, the message, experts say, is not to panic over an isolated ferritin value, but neither should a low ferritin be ignored simply. Thomas says medical advice is therefore important to determine whether iron deficiency is actually present, identify its cause and decide on the appropriate treatment and duration.
“Iron deficiency is a symptom of something else, not a disease on its own,” Dr. Thomas says.
