What does a ferritin level of 149 indicate?

Interpretation of a Ferritin Level of 149

A ferritin level of 149 ng/mL is within the normal range and generally indicates adequate iron stores, though interpretation should consider the patient's sex, age, and clinical context.

Normal Ferritin Ranges

• Normal ferritin levels in adults typically range:
  • Men: 24-336 ng/mL (average around 135 ng/mL) 1
  • Women: 11-307 ng/mL (average around 43 ng/mL) 1
• A ferritin level of 149 ng/mL falls within normal limits for both men and women 2, 1

Clinical Significance

• Ferritin is a storage protein that reflects iron stores in the liver, spleen, and bone marrow reticuloendothelial cells 2
• Each 1 μg/L (or ng/mL) of serum ferritin corresponds to approximately 10 mg of stored iron 1
• A value of 149 ng/mL indicates adequate iron stores and makes iron deficiency unlikely 2, 1

Interpreting Ferritin in Clinical Context

• Iron deficiency is unlikely when ferritin is >100 ng/mL in patients without inflammation 2
• In chronic inflammatory conditions, ferritin may be falsely elevated as it acts as an acute phase reactant 2
• For accurate assessment of iron status, ferritin should be interpreted alongside:
  • Transferrin saturation (TSAT) - values <20% suggest iron deficiency even with normal ferritin 2
  • Complete blood count to assess for anemia 1
  • Inflammatory markers (CRP, ESR) to rule out inflammation that might mask iron deficiency 1, 3

Special Considerations

Chronic Kidney Disease

• In CKD patients, ferritin should be maintained >100 ng/mL 2
• A level of 149 ng/mL is adequate for patients with CKD 2

Hemochromatosis Screening

• A ferritin of 149 ng/mL is below concerning thresholds for hemochromatosis 2
• Significant iron overload is typically associated with ferritin >1000 ng/mL 2
• For hemochromatosis screening, both ferritin and transferrin saturation should be measured 2

Obesity and Inflammation

• In overweight or obese individuals, ferritin may be elevated due to low-grade inflammation rather than reflecting true iron stores 4
• Consider inflammatory markers when interpreting ferritin in patients with obesity 4

Common Pitfalls in Ferritin Interpretation

• Relying on ferritin alone: Ferritin should be interpreted alongside transferrin saturation for a complete picture of iron status 2
• Ignoring inflammation: Ferritin is an acute phase reactant and may be falsely elevated in inflammatory states 2, 3
• Using inappropriate cutoffs: A ferritin level >50 μg/L can still be consistent with iron deficiency in the presence of inflammation 5
• Overlooking non-iron-related causes of elevated ferritin: Conditions such as malignancy, infection, and liver disease can cause hyperferritinemia independent of iron status 6

When Further Evaluation Is Needed

• If clinical suspicion for iron deficiency exists despite normal ferritin, consider:
  • Measuring transferrin saturation 2
  • Evaluating for chronic inflammation 1, 3
  • Assessing for symptoms of anemia 2, 1
• If screening for hemochromatosis, both ferritin and transferrin saturation should be measured 2