Spectrophotometric plasma iron determination from fingerpuncture specimens

Area of Science:

• Clinical Chemistry
• Hematology
• Analytical Chemistry

Background:

• Accurate plasma iron determination is crucial for diagnosing and managing various health conditions.
• Traditional methods require large sample volumes (2 ml), posing challenges for pediatric and field studies.
• A need exists for a sensitive, precise, and reproducible micromethod for plasma iron analysis.

Purpose of the Study:

• To develop and validate a simple, sensitive, and reproducible micromethod for plasma iron determination.
• To adapt the International Council for Standardization in Haematology (ICSH) reference procedure for micro-sample analysis.
• To assess the efficacy of the micromethod using fingerpuncture specimens.

Main Methods:

• Modification of the ICSH reference procedure using microcuvettes.
• Substitution of ferrozine for bathophenanthroline as the chromogen.
• Comparison of plasma iron values from paired fingerpuncture and venipuncture specimens analyzed by both micro- and ICSH-methods.

Main Results:

• The micromethod demonstrated high sensitivity, precision, and reproducibility.
• Identical mean plasma iron values (15.8 µmol/l or 88 µg/dl) were obtained using both methods.
• A strong correlation (r = 0.92, p < 0.0001) was observed between the micromethod and ICSH method.
• The micromethod was successfully applied in a field study of 429 children.

Conclusions:

• The developed micromethod provides a simple, sensitive, and reliable alternative for plasma iron determination.
• This method significantly reduces the required sample volume to 50 microliters.
• The micromethod is suitable for pediatric blood collection and field studies, facilitating wider iron status assessment.