What is the interpretation of elevated ferritin, low folate, and high vitamin B12 levels?

Interpretation of Laboratory Results

Your laboratory results suggest a pattern consistent with anemia of chronic disease (ACD) or functional iron deficiency, with borderline low folate and markedly elevated vitamin B12 that requires investigation for underlying inflammatory or chronic conditions. 1

Ferritin 461 ng/mL: Elevated and Potentially Misleading

• Ferritin at 461 ng/mL is elevated and primarily indicates an inflammatory state rather than adequate iron stores. 1
• In the presence of inflammation, ferritin levels between 100-700 μg/L can indicate either functional iron deficiency or inflammatory iron block, despite appearing "normal" or elevated. 1
• Ferritin is an acute-phase reactant that increases during inflammation, making it unreliable as a sole indicator of iron status in chronic disease states. 1, 2
• This elevated ferritin can mask concurrent iron deficiency, leading to inadequate treatment if interpreted in isolation. 1

Transferrin 202 mg/dL: Context-Dependent Interpretation

• Transferrin levels must be interpreted alongside transferrin saturation (TSAT), which is calculated from serum iron and total iron binding capacity. 2
• Transferrin saturation <20% with ferritin 100-700 μg/L indicates functional iron deficiency, which may respond to IV iron supplementation. 1
• TSAT is more reliable than ferritin alone for assessing iron available for erythropoiesis, as it is less affected by inflammation. 2
• Request calculation of transferrin saturation to properly interpret your iron status. 1

Folate 6.85 ng/mL: Borderline Low

• Folate at 6.85 ng/mL is in the lower range and may contribute to impaired erythropoiesis, particularly if you have increased cell turnover or are on certain medications. 2
• Low folate can cause macrocytic anemia and impair response to erythropoietin therapy. 2
• Folate deficiency occurs infrequently but should be corrected if detected, especially before initiating erythropoiesis-stimulating agents. 2
• Consider folate supplementation (400 μg daily for general use, or 5 mg daily if taking sulfasalazine or with small bowel disease). 2

Reticulocyte Hemoglobin 29.4 pg: Low

• Reticulocyte hemoglobin (CHr) of 29.4 pg is low and indicates insufficient iron availability for new red blood cell production, suggesting functional iron deficiency. 2
• CHr has sensitivities and specificities equal to or greater than ferritin and transferrin saturation in identifying functional iron deficiency. 2
• This finding supports that despite your elevated ferritin, iron is not adequately available for erythropoiesis. 1

Vitamin B12 865 pg/mL: Markedly Elevated

• Vitamin B12 at 865 pg/mL is significantly elevated and warrants investigation for underlying conditions including liver disease, myeloproliferative disorders, or certain malignancies. 3
• Elevated B12 is not typically concerning for toxicity but can be a marker of serious underlying disease. 3
• This elevation is inconsistent with B12 deficiency as a cause of anemia. 2

Clinical Synthesis and Recommended Actions

Your pattern suggests anemia of chronic disease with functional iron deficiency:

1. Assess for underlying inflammatory or chronic conditions by measuring CRP and ESR alongside your iron parameters. 1

2. Calculate transferrin saturation using serum iron and TIBC to definitively diagnose functional iron deficiency (TSAT <20% with ferritin 100-700 ng/mL). 1

3. If TSAT <20% is confirmed, consider IV iron supplementation (50-125 mg weekly for 8-10 doses) rather than oral iron, as systemic inflammation inhibits oral iron absorption. 2, 1

4. Supplement folate given borderline low levels, particularly if you have active inflammatory bowel disease, are taking certain medications, or have increased cell turnover. 2

5. Investigate the cause of elevated vitamin B12 through liver function tests and consideration of hematologic evaluation if other abnormalities are present. 3

6. Obtain a complete blood count to assess mean corpuscular volume (MCV), hemoglobin, and evaluate for abnormalities in multiple cell lines that would warrant hematology consultation. 2

Critical Pitfall to Avoid

Do not assume adequate iron stores based solely on elevated ferritin in the setting of inflammation. 1 The combination of elevated ferritin, low reticulocyte hemoglobin, and need for transferrin saturation assessment indicates that functional iron deficiency is likely present despite the seemingly reassuring ferritin level. 1, 2