What laboratory investigations should be performed next in a patient with elevated serum ferritin?

Next Steps for Elevated Ferritin

Measure transferrin saturation (TSAT) simultaneously with ferritin, because TSAT elevation characterizes hereditary hemochromatosis while ferritin alone is unreliable due to its elevation in inflammation, malignancy, liver disease, and metabolic conditions. 1

Initial Laboratory Workup

• Order transferrin saturation alongside repeat ferritin measurement to distinguish true iron overload from secondary causes of hyperferritinemia. 1
• Elevated TSAT (>45-60%) suggests hereditary hemochromatosis, whereas normal TSAT with high ferritin points toward inflammatory, metabolic, or malignant etiologies. 1, 2
• Serum iron and TSAT are more prognostically meaningful than ferritin alone in many clinical contexts, as ferritin is an acute-phase reactant that rises independently of iron stores. 3, 1

Genetic Testing When Indicated

• Perform HFE genetic testing (C282Y and H63D mutations) in all patients with elevated TSAT and ferritin to diagnose hereditary hemochromatosis. 1
• C282Y homozygosity defines classic hemochromatosis; compound heterozygotes (C282Y/H63D) account for 14–30% of patients requiring phlebotomy. 1
• H63D homozygosity rarely causes clinically significant iron overload (only ~3% develop true overload). 1

Imaging for Tissue Iron Quantification

• MRI with R2 relaxometry is the preferred non-invasive test to quantify hepatic iron concentration* when the cause of hyperferritinemia remains unclear after initial labs or when biochemical iron overload is confirmed. 3, 1
• MRI R2 provides the most accurate detection and quantification of iron overload* in liver, pancreas, heart, spleen, and brain, eliminating the need for liver biopsy in most cases. 3
• A single MRI examination can simultaneously assess multiple organs, aiding differential diagnosis: early hereditary hemochromatosis shows predominant hepatic iron with minimal splenic involvement, whereas ferroportin disease and transfusional overload display increased splenic iron. 3
• Hepatic R2 correlates linearly with total body iron stores* and predicts the number of therapeutic phlebotomies required. 3, 1
• Cardiac MRI should be performed in patients with cardiac symptoms or juvenile hemochromatosis, as liver iron does not correlate with cardiac iron burden. 1

When to Order MRI

• Order MRI when TSAT >60% or when TSAT <60% but ferritin >963–1000 µg/L, as these thresholds identify >95% of patients with severe hepatic iron overload (liver iron concentration >7 mg/g). 2, 1
• MRI is also indicated when genetic testing is negative but clinical suspicion for non-HFE hemochromatosis persists. 1

Role of Liver Biopsy

• Liver biopsy is NOT recommended for diagnosing hepatic iron overload when MRI is available, given MRI's superior accuracy and non-invasiveness. 3, 1
• Reserve biopsy for C282Y homozygotes or compound heterozygotes with ferritin >1000 µg/L or elevated liver enzymes (ALT/AST) to assess for fibrosis or cirrhosis. 1
• Biopsy is essential for non-HFE iron overload to determine iron distribution pattern and severity. 1
• Do not biopsy when cirrhosis is already clinically evident, as it adds no diagnostic value. 1

Exclude Secondary Causes of Hyperferritinemia

• Evaluate for non-iron-overload causes: chronic inflammation, malignancy (the most common cause in one large series), infection, alcohol excess, non-alcoholic fatty liver disease (NAFLD), metabolic syndrome, chronic liver disease (hepatitis B/C), and hemolytic anemia. 1, 4, 5
• Ninety percent of elevated ferritin is due to conditions other than iron overload, where phlebotomy is not indicated. 5
• In a tertiary-care cohort with ferritin >1000 µg/L, malignancy was the most frequent cause (153/627 patients), followed by iron-overload syndromes (136/627). 4

Common Pitfalls

• Do not rely on ferritin alone—it rises in inflammation, malignancy, and chronic liver disease independent of iron stores. 1
• Do not assume all hyperferritinemia represents iron overload; systematically exclude metabolic syndrome, alcohol, NAFLD, and inflammatory conditions. 1
• Ultrasound and CT provide little quantitative information on liver iron and are not recommended for iron overload assessment. 3

Algorithmic Summary

1. Measure TSAT and repeat ferritin to differentiate iron overload from secondary causes. 1
2. If TSAT elevated: order HFE genetic testing (C282Y, H63D). 1
3. If TSAT >60% or ferritin >963–1000 µg/L with any TSAT: proceed to MRI R2* for hepatic iron quantification. 2, 1
4. If genetic testing positive (C282Y homozygote or compound heterozygote) and ferritin >1000 µg/L or elevated liver enzymes: consider liver biopsy for fibrosis staging. 1
5. If TSAT normal and ferritin elevated: investigate for inflammation, malignancy, liver disease, metabolic syndrome, or alcohol excess. 1, 5
6. If cause unclear or non-HFE iron overload suspected: MRI R2* and consider referral to gastroenterology or hematology. 1, 5