Blood protoporphyrin IX as a biological indicator of increased absorption of lead.

Blood lead and erythrocyte zinc-protoporphyrin levels were studied in 45 male adults exposed to lead (traditional home-factory pottery) and compared with two control populations. These two variables are well correlated in all the studied populations. Delta-aminolevulinic acid levels in urine (ALA-U) were significantly higher in the exposed group. Hemoglobin concentration (Hb), hematocrit (Hc) values and clinical data were also considered. We conclude that the zinc-protoporphyrin method here used is a simple reliable field test of the selection of individuals who need more detailed clinical investigation.