Some factors affecting the utility of bovine blood as a control material in lead-screening programs

Bovine blood is used frequently as control material in interlaboratory comparisons for blood-lead analysis, but an erythrocyte protoporphyrin control material is needed. We present data on the rate of changes in blood lead and erythrocyte protoporphyrin in steers fed lead acetate. We also show, by comparison of fluorescence spectra with those of known compounds, that most of the porphyrin in lead-burdened steers probably exists as free protoporphyrin IX along with some zinc-complexed protoporphyrin IX. Bovine blood is suitable as an erythrocyte protoporphyrin control material for laboratories using acid extraction procedures, but not for the proficiency testing of laboratories using hematofluorometers.