A radioimmunoassay for serum ferritin

Area of Science:

• Clinical Chemistry
• Immunology
• Hematology

Background:

• Serum ferritin is a key indicator of iron status.
• Accurate measurement of serum ferritin is crucial for diagnosing iron deficiency.

Purpose of the Study:

• To develop and evaluate a novel radioimmunoassay for serum ferritin.
• To establish reference intervals and assess the assay's diagnostic utility for iron deficiency.

Main Methods:

• Development of a radioimmunoassay using 125I-labeled ferritin and specific antibodies.
• Utilized goat anti-rabbit gamma-globulin and polyethylene glycol for separation.
• Assayed serum samples with a working range up to 500 µg/L and 75 µL sample volume.

Main Results:

• The assay demonstrated high sensitivity (1.5 µg/L) and long-term precision (CV 13%).
• Established reference intervals: men (18-330 µg/L), women >50 years (18-200 µg/L).
• Serum ferritin <18 µg/L correlated with absent bone marrow iron, indicating iron deficiency.

Conclusions:

• The developed radioimmunoassay is a sensitive and precise tool for measuring serum ferritin.
• Serum ferritin levels below 18 µg/L are a reliable indicator of iron deficiency.
• The assay aids in the diagnosis of iron deficiency across different demographic groups.