An improved capillary blood-filter paper-graphite furnace atomic absorption spectrometric method for lead screening

Area of Science:

• Analytical Chemistry
• Environmental Health
• Clinical Diagnostics

Background:

• Accurate blood lead level (BLL) monitoring is crucial for public health, especially in children.
• Traditional venous blood sampling can be invasive and challenging for routine screening.
• Filter paper (FP) collection offers a less invasive alternative for blood sample collection.

Purpose of the Study:

• To describe and validate a revised procedure for processing capillary blood samples on filter paper (FP) for lead analysis using graphite furnace atomic absorption spectrometry (GFAAS).
• To assess the accuracy, reliability, and practicality of the FP method compared to traditional venous blood sampling for lead screening.

Main Methods:

• A revised protocol for processing dried capillary blood spots from filter paper (FP) using GFAAS was developed.
• A 1/4-inch diameter disk was punched from FP samples for analysis.
• Results from FP samples were compared with corresponding venous blood samples, analyzing variables like hematocrit and filter paper blanks.

Main Results:

• A high correlation (0.975) was observed between FP and venous blood lead results.
• The revised FP method demonstrated low false-positive (0.8%) and false-negative (1.7%) rates.
• No significant differences were found for samples with hematocrit values of 30-39%, and filter paper blanks were minimal (< 2 µg/dL without correction, 0.1 µg/dL with correction).
• Environmental lead contamination was not detected during a year-long urban sampling study.

Conclusions:

• The revised FP method is a simpler, accurate, and reliable technique for lead screening using capillary blood.
• Fingerstick capillary blood collection on filter paper is suitable for widespread lead screening programs.
• Adherence to proper contamination precautions is essential for accurate results.