Spot ferritin assay for serum samples dried on filter paper

Area of Science:

• Biochemistry
• Clinical Chemistry
• Hematology

Background:

• Ferritin is a key indicator of iron status.
• Traditional ferritin assays require fresh serum samples, posing logistical challenges for field studies.
• A simplified, stable method for ferritin analysis is needed.

Purpose of the Study:

• To develop and validate a novel spot method for serum ferritin analysis.
• To assess the accuracy and reliability of the spot method compared to traditional assays.
• To evaluate the stability of ferritin in spotted samples under various storage conditions.

Main Methods:

• A spot method was developed using 20-microL serum samples dried on filter paper.
• Samples were incubated with cellulase, centrifuged, and the supernatant was assayed for ferritin via radioimmunoassay.
• Sample stability was tested after storage at room temperature, refrigerated, and frozen for up to 4 weeks.

Main Results:

• The spot method showed strong correlation (r = 0.98) with the traditional method for ferritin analysis.
• Ferritin values were not significantly different between the spot and traditional methods.
• Spotted samples stored at room temperature for 4 weeks yielded comparable ferritin values, with only a minor increase (2.2 micrograms/L).
• The spot method accurately classified individuals as iron sufficient or deficient (< 15 micrograms/L).

Conclusions:

• The spot ferritin method is a reliable, accurate, and practical tool for iron status assessment in field settings.
• Room temperature storage of spotted samples for up to 4 weeks eliminates the need for freezing.
• This method facilitates the use of capillary blood, reducing costs and concerns associated with venipuncture.