Can high ferritin with normal iron and transferrin saturation reflect inflammation rather than iron overload?

Elevated serum ferritin in the presence of normal circulating iron and transferrin saturation (TSAT < 45%) is a frequent clinical finding. Approximately 90% of hyperferritinemia cases stem from secondary reactive processes rather than hereditary iron overload. A normal TSAT has a high negative predictive value (~97%) for classic genetic hemochromatosis, directing clinical focus toward metabolic or inflammatory triggers.

Mechanistic explanations

• Cytokine-driven synthesis: Inflammatory cytokines, particularly interleukin-6 (IL-6), directly upregulate the transcription of ferritin—a positive acute-phase reactant—within hepatocytes, entirely independent of total body iron stores.
• Hepcidin-mediated sequestration: Inflammation increases the expression of the hormone hepcidin. Elevated hepcidin sequesters iron within macrophages and hepatocytes, which prevents its export into the bloodstream. This cellular trapping keeps circulating iron and TSAT within normal ranges despite high intracellular ferritin storage.
• Metabolic and tissue factors: Conditions like metabolic syndrome and metabolic dysfunction-associated steatotic liver disease (MASLD) drive dysmetabolic hyperferritinemia. Cellular stress and subclinical hepatocyte damage lead to the passive leakage of intracellular ferritin into the systemic circulation.

Diagnostic evaluation to resolve the trigger

• Inflammatory and infection markers: C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are required to confirm or rule out an active systemic inflammatory response.
• Liver and toxin assessment: Liver function tests and abdominal ultrasound evaluate for fatty liver changes and alcohol-related tissue injury, which are highly prevalent secondary causes.
• Selective genetic testing: HFE genotyping is necessary to rule out primary hereditary hemochromatosis, particularly if follow-up testing reveals a fluctuating or elevated TSAT ($\ge$ 45%).

Bottom line

• Isolated high ferritin with normal transferrin saturation is primarily a marker of cellular stress, inflammation, or metabolic dysfunction rather than iron overload; identifying the precise trigger requires a systematic evaluation of inflammatory markers, liver health, and selective genetic testing.