Interlaboratory comparison of lead and cadmium in blood, urine, and aqueous solutions

Analysis for lead and cadmium in biological liquids (blood and urine) is difficult. Results of such analyses from five laboratories are compared for samples with known additions of lead and cadmium. The data, evaluated in terms of inter- and intralaboratory reproducibility and accuracy, suggest that laboratories should voluntarily participate in quality control programs. Users of routine laboratories are advised to use their own quality control program.