Interpretation of the iron panel

Interpreting an iron panel requires integration of multiple laboratory markers, clinical context, and consideration of underlying conditions that may affect iron metabolism.

Key components of an iron panel and their interpretation include:

• Serum Iron: Measures circulating iron bound to transferrin; low levels suggest iron deficiency or functional iron restriction, while high levels may indicate iron overload NICE CKS Saboor et al. 2026.
• Serum Ferritin: Reflects iron stores but is also an acute-phase reactant, increasing in inflammation and chronic disease. Low ferritin is specific for iron deficiency; however, normal or high ferritin does not exclude deficiency in inflammatory states NICE CKS Saboor et al. 2026.
• Transferrin and Transferrin Saturation (TSAT): Transferrin is the iron transport protein; TSAT is the ratio of serum iron to total iron-binding capacity, indicating the proportion of transferrin saturated with iron. Low TSAT (<20%) suggests iron deficiency, while high TSAT (>45–50%) may indicate iron overload NICE CKS Morel et al. 2026.
• Additional Markers: In complex or unclear cases, measurement of hepcidin, soluble transferrin receptor, or novel biomarkers such as fibrinogen-like protein 1 (FGL1) can help differentiate iron deficiency from anemia of chronic disease NICE CKS Saboor et al. 2026.

Clinical interpretation steps:

• Iron deficiency anemia (IDA) is typically characterized by low serum iron, low ferritin, low TSAT, and hypochromic microcytic anemia NICE CKS.
• Anemia of chronic disease (ACD) or functional iron deficiency may present with low serum iron and TSAT but normal or elevated ferritin due to inflammation; C-reactive protein (CRP) and clinical context are essential for interpretation NICE CKS Saboor et al. 2026.
• Use of markers such as FGL1 may improve diagnostic accuracy particularly where ferritin is raised by inflammation, as FGL1 aligns with iron-restricted erythropoiesis and is elevated in iron deficiency states independent of inflammation NICE CKS Saboor et al. 2026.
• Genetic testing such as clinical exome sequencing can identify rare or digenic hereditary causes of iron overload or hyperferritinemia when standard iron panels are inconclusive, guiding diagnosis and management NICE CKS Morel et al. 2026.

Additional considerations: Interpret iron indices alongside full blood count parameters and clinical features.

• Microcytic hypochromic anemia strengthens the diagnosis of IDA NICE CKS.
• Inflammatory markers such as CRP help distinguish true iron deficiency from inflammation-driven ferritin elevation NICE CKS Saboor et al. 2026.
• Rare inherited variants affecting iron metabolism may present with atypical patterns; comprehensive genetic panels assist in diagnosing unexplained hyperferritinemia NICE CKS Morel et al. 2026.

Summary of approach: Assess serum iron, ferritin, transferrin saturation, hemoglobin indices, and inflammatory markers in clinical context. Consider measuring additional markers like FGL1 or hepcidin for complex cases. Use genetic testing when indicated in unexplained iron disorders.