Adequacy of capillary lead specimens

In response to the increased demand for reliable alternatives to venous lead testing, the Centers for Disease Control has called for increased research into using capillary methodologies. In the past, there have been problems with this procedure, primarily because of external lead contamination falsely elevating values. A three tiered approach was developed to assess the adequacy of capillary lead specimens. The first approach involved examination of a large database of capillary and venous samples for obvious differences. The second, approach involved analysis of elevated lead follow-ups for indications of gross contamination. The last approach involved experimentation to determine if hand washing eliminates gross contamination. Obvious differences were found between the venous and capillary databases. Gross contamination was rare, but the data suggest variables minor contamination. The analysis of elevated lead follow-ups demonstrated that gross contamination is sometimes present, but more likely to decrease in follow up results is due to day to day fluctuations in lead levels and decreases in minor contamination. Experimentation demonstrated that hand washings greatly reduces the amount of external lead contamination. Capillary lead testing should be considered a viable alternative to venous testing, provided that the patient and collector are meticulous in detail.