Can you be iron deficient even with normal haemoglobin levels?

Iron deficiency can develop even when blood tests show normal levels of haemoglobin, which is the protein in red blood cells responsible for oxygen transport. This is because haemoglobin and ferritin, the latter of which measures iron reserves, are different indicators. An individual's body can maintain normal haemoglobin levels for a while by tapping into its iron reserves.

Ferritin acts as a "warehouse" for iron storage, which is predominantly found in tissues like the liver and spleen, as well as within cells known as macrophages. These iron reserves are then utilized for erythropoiesis, the process that produces red blood cells and haemoglobin. Therefore, iron deficiency can be overlooked if only haemoglobin levels are analyzed.

In India, the most recent data (NFHS-5) indicated that 57% of women aged 15-49 years suffer from anaemia. While ferritin is an essential marker for iron stores, it cannot be interpreted in isolation as the "normal" value varies depending on factors such as age, sex, pregnancy, menstruation, and the person's clinical history. Moreover, ferritin is considered an acute-phase reactant, meaning its levels may increase during an infection or inflammation, potentially masking a true iron deficiency.

Despite this, a ferritin value falling within the laboratory's reference range does not necessarily rule out iron deficiency in someone experiencing inflammation or chronic illness. Iron loss through heavy or prolonged menstrual bleeding, pregnancy, frequent blood donation, vegetarian diets, or chronic, unnoticed blood loss due to conditions like ulcers or bleeding piles can all contribute to gradually declining iron stores.

Consequently, low ferritin levels can be a crucial indicator of iron deficiency, even when haemoglobin remains normal.

It's essential to note that iron deficiency and iron-deficiency anaemia share vague symptoms that overlap with various other conditions. These symptoms may include headache, body and muscle aches, itching, spells of blackout, ringing in the ears, breathlessness, persistent tiredness, weakness, hair loss, and poor concentration. However, these symptoms alone should not prompt the decision to start iron supplementation, as they do not definitively indicate iron deficiency.

A complete blood count is a crucial starting point for assessment, followed by ferritin and other iron parameters to determine if depleted iron stores are contributing to the individual's health issues.

It is vital to address the underlying cause of iron deficiency rather than simply treating the deficiency with iron supplements. Iron deficiency is merely a symptom, not a disease itself. Treatment typically continues for several months, even after haemoglobin levels improve, to replenish iron stores. However, the appropriate dose and duration of treatment depend on the cause and severity of the deficiency, and needless supplementation may lead to side effects such as nausea, constipation, and abdominal discomfort.

Furthermore, excessive iron accumulation can be harmful, particularly in individuals with conditions that lead to increased iron absorption. Therefore, it is crucial not to panic over an isolated ferritin value but to seek medical advice to determine whether iron deficiency is indeed present, identify its cause, and decide on the appropriate treatment and duration.