What is the interpretation of Ferritin levels?

From the Guidelines

Ferritin levels should be interpreted as follows: in the absence of inflammation, a serum ferritin level < 30 mg/L indicates iron deficiency, while in the presence of inflammation, a serum ferritin level up to 100 mg/L may still be consistent with iron deficiency. The interpretation of ferritin levels is crucial in diagnosing and managing iron deficiency anemia, particularly in patients with chronic diseases such as kidney disease or inflammatory bowel disease 1. When evaluating ferritin levels, it is essential to consider the presence or absence of inflammation, as ferritin is an acute-phase reactant that can increase in response to inflammation, making it a less reliable indicator of iron stores in these situations 1. In patients without inflammation, a serum ferritin level < 30 mg/L is a reliable indicator of iron deficiency, while in patients with inflammation, a serum ferritin level up to 100 mg/L may still indicate iron deficiency 1. Some key points to consider when interpreting ferritin levels include:

• In the absence of inflammation, a serum ferritin level < 30 mg/L indicates iron deficiency
• In the presence of inflammation, a serum ferritin level up to 100 mg/L may still be consistent with iron deficiency
• Ferritin levels should be interpreted in conjunction with other laboratory tests, such as transferrin saturation and serum iron, to accurately diagnose and manage iron deficiency anemia
• The presence of inflammation can affect the interpretation of ferritin levels, and other markers of inflammation, such as C-reactive protein (CRP), should be considered when evaluating ferritin levels 1. Overall, the interpretation of ferritin levels requires careful consideration of the clinical context, including the presence or absence of inflammation, and should be used in conjunction with other laboratory tests to accurately diagnose and manage iron deficiency anemia.

From the Research

Interpretation of Ferritin Levels

Ferritin levels are used to assess iron stores in the body. The interpretation of these levels can be complex, as they can be influenced by various factors such as inflammation and underlying medical conditions.

• Ferritin levels below 50 ng/mL may indicate early iron deficiency, as suggested by a study published in 2022 2.
• A ferritin level of < 12-20 μg/L is commonly used as a diagnostic cut-off for iron deficiency, but this may not be sensitive enough to detect iron deficiency in all cases 3.
• Increasing the diagnostic cut-off to 30 μg/L may improve sensitivity for detecting iron deficiency, although this may also reduce specificity 3.
• In patients with inflammatory conditions, serum ferritin levels may not accurately reflect iron stores, and a higher threshold of < 100 μg/L or transferrin saturation (TSAT) < 20% may be considered diagnostic for iron deficiency 4.
• Functional limits based on the association between ferritin and erythrocyte parameters suggest that iron deficiency anemia starts to occur when ferritin levels reach 10 µg/L 5.

Factors Influencing Ferritin Levels

Several factors can influence ferritin levels, including:

• Inflammation: Ferritin is an acute-phase reactant that becomes elevated in response to inflammation, which can complicate the diagnosis of iron deficiency 6, 4.
• Underlying medical conditions: Conditions such as chronic heart failure, chronic kidney disease, and inflammatory bowel disease can affect iron stores and ferritin levels 4.
• Age and gender: Ferritin levels can vary depending on age and gender, particularly in pediatric populations 5.

Clinical Applications

Ferritin levels have several clinical applications, including:

• Diagnosing iron deficiency and iron deficiency anemia 2, 3, 5, 4.
• Monitoring iron stores in patients with underlying medical conditions 6, 4.
• Guiding treatment decisions for iron deficiency and iron deficiency anemia 5, 4.