Three commercial methods for serum ferritin compared and the high-dose "hook effect" eliminated

Area of Science:

• Clinical Chemistry
• Immunology
• Hematology

Background:

• Serum ferritin is a key biomarker for iron status.
• Accurate measurement of serum ferritin is crucial for diagnosing iron deficiency and overload.
• Several commercial kits based on different immunoassay techniques are available.

Purpose of the Study:

• To evaluate the performance of four commercial serum ferritin assay kits.
• To compare the sensitivity, precision, and accuracy of immunoradiometric, radioimmunoassay, and enzyme immunoassay techniques.
• To assess the utility of these kits in diagnosing iron deficiency anemia and iron overload.

Main Methods:

• Evaluation of four commercial serum ferritin kits (Abbott Laboratories, Clinical Assays, Corning Medical, Ramco).
• Utilized immunoradiometric assay (IRMA), radioimmunoassay (RIA), and enzyme immunoassay (EIA) techniques.
• Assessed kit performance based on sensitivity, precision, and inter-kit comparison across various ferritin concentration ranges.

Main Results:

• Two IRMA kits demonstrated satisfactory sensitivity and precision for diagnosing uncomplicated iron-deficiency anemia.
• One IRMA kit exhibited a high-dose hook effect at 10 mg/L, which was mitigated through modification to 33 mg/L.
• Significant inter-kit variability was observed for serum ferritin concentrations above 300 µg/L.

Conclusions:

• Selected commercial kits are reliable for diagnosing iron-deficiency anemia.
• The performance variability of current kits raises concerns regarding their use in diagnosing iron overload.
• Further standardization and validation are needed for serum ferritin assays, particularly for high concentration measurements.