Routine blood tests that show normal haemoglobin levels may not fully capture underlying iron deficiencies, experts say, highlighting the importance of measuring ferritin to assess iron stores in the body. While haemoglobin reflects the blood’s ability to carry oxygen, ferritin serves as a marker of stored iron and can decline well before anaemia develops.

Medical professionals caution that normal haemoglobin results can mask depleted iron reserves. Dr Yousef Said, Medical Director at Metabolic, explained that haemoglobin is a late indicator of iron deficiency. “The body uses its remaining iron stores to maintain haemoglobin levels initially, so ferritin levels drop first,” he said. Dr Azeem Irshad, a Specialist in Internal Medicine at Aster Clinic in Dubai, echoed this view, noting that iron deficiency may exist without anaemia and that stored iron is typically depleted first.

Ferritin levels are measured in nanograms per millilitre (ng/mL), with levels below 30 ng/mL generally indicating low iron stores and values under 15 ng/mL providing strong evidence of iron deficiency, according to Dr Said. However, doctors emphasize that ferritin results should be interpreted alongside haemoglobin, full blood counts, and other iron markers rather than in isolation. Factors such as symptoms, medical history, and additional tests play a critical role in determining the cause and significance of low ferritin.

An additional complexity is that ferritin can increase as part of the body’s inflammatory response, potentially obscuring iron deficiency when inflammation or chronic disease is present. Dr Azeeza Safwan Amoori, a Specialist in Internal Medicine at Medicare Medical Centre, warned that normal ferritin levels do not rule out iron deficiency under such conditions. Physicians often use other indicators, such as transferrin saturation, serum iron, total iron-binding capacity, and markers of inflammation like C-reactive protein, to gain a clearer picture of iron status.

Symptoms associated with low ferritin vary widely and may include fatigue, reduced exercise tolerance, difficulty concentrating, and restless legs. Some individuals, however, may experience no noticeable symptoms despite having depleted iron reserves. Dr Azeeza explained that these nonspecific symptoms often overlap with conditions like stress, poor sleep, thyroid disorders, and other nutritional deficiencies, complicating diagnosis.

If iron deficiency advances to anaemia, more prominent symptoms such as shortness of breath on exertion, dizziness, palpitations, weakness, and pallor may develop, signaling the need for prompt medical evaluation. Still, health professionals stress that symptoms alone cannot confirm iron deficiency; comprehensive blood tests and clinical assessments are essential.

Despite consumption of iron-rich foods or supplements, some individuals may continue to have low ferritin levels due to factors such as impaired absorption, ongoing blood loss, or inflammatory conditions. This underscores the need for thorough investigation when low iron stores persist despite supplementation, rather than simply increasing dosage without understanding the underlying cause.