The correlation between paired, simultaneously drawn extraction method filter paper and venous samples is >.970.  Additionally, undetected-elevated and, falsely-elevated rates may be considered clinically insignificant. These findings are documented by three published, peer-reviewed studies involving 363 paired, simultaneously drawn extraction method filter paper and venous sample comparisons.

References:

 Hugh Y. Yee et al.  Capillary Blood Collection by Paper for Lead Analysis by Graphite Furnace Atomic Absorption Spectrometry.  Microchemical Journal, 52:  370-375 (1995).

 Keyrati Srivuthana et al.  A New Filter Paper Method to Measure Capillary Blood Lead Level in Children.  Arch. Pediatr. Adolesc. Med., 150:  498-502 (1996).

 Hugh Y. Yee.  An Improved Capillary Blood-Filter Paper-Graphite Furnace Atomic Absorption Spectrometric Method for Lead Screening.  Journal of Analytical Toxicology, Vol. 21:  142-148 (1997).