A pilot study of lead and cadmium exposure in young children in Stockholm, Sweden: methodological considerations using capillary blood microsampling.

A capillary blood microsampling technique was tested among urban young children in Stockholm. Blood lead (BPb) and hemoglobin (Hb) concentrations were determined in capillary blood obtained by fingerstick from 41 children, 13-20 months old, and the accompanying parent. The quality control included control for lead (Pb) and cadmium (Cd) contamination of material and equipment used for blood sampling, washing procedures for the hands and fingers to be punctured, comparisons of Pb and Cd concentrations in blood obtained by fingerstick and by brachial vein puncture from the same individuals, analysis of external quality control samples for Pb and Cd in blood together with the collected samples, and evaluation of the analytical performance using linear regression analysis. The results showed that blood sampling material may contaminate the blood samples with amounts of Pb and Cd that would seriously influence the monitoring results in the low concentration range (< 100 micrograms Pb/L and < 1 microgram Cd/L). However, it is possible to obtain reliable BPb concentrations (> 10 micrograms Pb/L), but not BCd concentrations (< 1 microgram Cd/L), with the capillary blood microsampling technique tested provided that a strict quality control is applied. The sampling procedure tested was well accepted by the children and their parents. The children's median BPb concentration (27 micrograms/L; range 9-73 micrograms/L) was similar to the median BPb concentration of their parents (27 micrograms/L; range 7-74 micrograms/L). However, the correlation between child and parent BPb concentrations was poor (R2 = 0.20), which may indicate different sources to Pb exposure in children and parents.