In a 33-year-old woman with mild hyperbilirubinemia, mildly elevated alanine aminotransferase, ferritin approximately 332 ng/mL, serum iron 179 µg/dL, total iron‑binding capacity 351 µg/dL and transferrin saturation 51 %, what is the most appropriate next step in management?

Genetic Testing for Hemochromatosis

The most appropriate next step is to perform genetic testing for HFE mutations (C282Y and H63D) to confirm or exclude hereditary hemochromatosis, given the elevated transferrin saturation of 51% combined with elevated ferritin and liver enzyme abnormalities. 1

Rationale for Genetic Testing

This 33-year-old woman presents with a classic triad suggestive of iron overload:

• Transferrin saturation of 51% (elevated, threshold >45% in women) 1
• Ferritin 332 ng/mL (elevated for a premenopausal woman) 1
• Mildly elevated ALT with hyperbilirubinemia (suggesting hepatic involvement) 2, 3

The combination of elevated transferrin saturation with hyperferritinemia is the hallmark biochemical pattern of hereditary hemochromatosis and warrants genetic testing. 4, 5 Transferrin saturation >50% is specifically associated with disturbed plasma iron homeostasis characteristic of hemochromatosis. 1

Diagnostic Algorithm

Primary Evaluation Steps:

• Genetic testing is systematically indicated when transferrin saturation is elevated in the setting of hyperferritinemia 4
• The association of raised ALT activity with transferrin saturation >60% provides a cost-effective method for detecting clinical hemochromatosis, though this patient's saturation of 51% still warrants investigation 2
• Recent evidence shows that transferrin saturation >60% combined with ferritin levels are the main predictors of significant liver iron content 6

What to Test:

• HFE gene mutations: C282Y and H63D variants 1, 4
• If HFE testing is negative but iron overload is confirmed, consider second-line genetic testing for non-HFE hemochromatosis 4, 3

Additional Concurrent Workup

While awaiting genetic results, the following should be obtained:

• Hepatitis B surface antigen and hepatitis C antibody to exclude viral hepatitis as a cause of elevated transaminases and hyperferritinemia 5
• Metabolic syndrome assessment (waist circumference, blood pressure, fasting lipids, glucose/A1C) as nonalcoholic fatty liver disease is a common cause of mild transaminase elevation 5
• Alcohol consumption history as this can elevate both transferrin saturation and ferritin 1
• Complete blood count to assess for anemia or other hematologic abnormalities 5

Role of MRI

MRI for hepatic iron quantification should be considered if:

• Genetic testing is negative or inconclusive but biochemical iron overload persists 1
• There are additional risk factors (metabolic syndrome, alcohol use) that complicate the picture 1
• Transferrin saturation >60% with ferritin >963 μg/L, which predicts severe liver iron content (>7 mg/g) with 95% accuracy 6

For this patient with transferrin saturation of 51% and ferritin 332 ng/mL, MRI is not immediately necessary if she is homozygous for C282Y, as the diagnosis can be made biochemically and genetically. 1 However, MRI would be valuable if genetic testing is negative or shows compound heterozygosity. 1

Important Caveats

• Hyperferritinemia is nonspecific: Only 10% of hyperferritinemia cases are due to true iron overload; the remainder are reactive or inflammatory 7
• Transferrin saturation can remain elevated even during appropriate treatment of hemochromatosis when ferritin normalizes 1
• Autoimmune hepatitis can mimic iron overload: Rarely, autoimmune hepatitis presents with elevated transferrin saturation, so if genetic testing is negative, consider checking ANA, ASMA, and immunoglobulins 8
• Non-HFE hemochromatosis exists: If clinical suspicion remains high despite negative HFE testing, pursue additional genetic panels 4, 3

What NOT to Do

• Do not delay genetic testing to pursue extensive imaging first in a patient with this biochemical profile 4
• Do not assume inflammatory causes when transferrin saturation is elevated alongside ferritin, as this pattern is more specific for iron overload 1, 7
• Do not start phlebotomy before confirming the diagnosis genetically and assessing disease severity 1