A simple fluorometric assay of protoporphyrin in erythrocytes (EPP) as a screening test for lead poisoning.

A simple microfluorometric procedure for the measurement of protoporphyrin in erythrocytes (EPP) is described. The technique, which can be performed in less than 4 minutes with portable equipment, utilizes 40 mul of capillary blood and only one reagent (94 percent acidified ethanol) for the extraction. The results obtained by this micromethod are in close agreement with those of the ethyl acetate/hydrochloric acid double-extraction methods. The EPP concentration increases markedly when the blood lead level is increased, and the test can be used to screen children for lead poisoning. This new micromethod also gives reproducible results when dried blood spots on filter paper are used instead of liquid blood.