Iron Deficiency Workup

Iron deficiency is a supply problem that develops when dietary intake and intestinal absorption cannot keep pace with physiological demand or ongoing losses. Storage iron falls first, reflected by ferritin. Transport iron, reflected in transferrin saturation, becomes restricted next. Haemoglobin may remain normal until later, so iron deficiency without anaemia is a genuine, treatable stage rather than a reassuring result. The workup has four questions: Is iron deficiency present? Has it caused anaemia? Why has iron become deficient? How urgently must the patient be assessed or treated? The answers determine whether the next step is oral replacement and outpatient follow-up, gastrointestinal investigation, urgent stabilization, or referral for IV iron. A low ferritin is usually straightforward. A normal or high ferritin is not necessarily reassuring because inflammation, infection, malignancy, liver disease, and obesity can raise ferritin independently of iron stores. Clinical interpretation must therefore match the patient’s context rather than rely on one number in isolation.