Conference paper
Screening for pediatric lead poisoning
J.J. Chisolm, Jr.
; John Hopkins Medical School, The John F. Kennedy Institute, Baltimore, Maryland, USA
Abstract
Prevention of injury to the developing nervous system in young children is dependent upon early detection of increased lead absorption during the preclinical stage of plumbism. Practical considerations Iimit the choice of screening tests in children to erythrocyte protoporphyrm (E.P) and blood lead (Pb-B) which can be performed on micro samples of blood, which in turn, can be obtained by finger prick. In lead poisoning and in iron deficiency states, zinc protoporphyrin IX is the porphyrin found in peripheral erythrocytes. Results obtained with portable equipment and a simple field EP test are repented here for three groups of children. Simple EP tests serve as an inexpensive preliminary epidemiological tool to detect groups with increased Iead absorption. This was demonstrated in relation to a stationary point source of exposure to lead: Preliminary screening with an EP test (which was later confirmed by extensive BP and Pb-B tests throughout the entire metropolitan area of El Paso, Texas, USA) indicated that increased lead absorption occurred in children residing in close proximity to the stationary point source, but not ·in those children residing far away. Dose-response (population response rate) data were determined prospectively in a well child clinic setting in an old housing area in Baltimore, Maryland in 155 preschool children. A 50 per cent positive response rate was found in those with Pb-B in the 40-49 µg percent range and a 95 percent positive response rate was found in those with Pb-B > 5O µg percent. Longitudinal trends in Pb-B and EP were determined in a cohort of 342 children who were tested at three month intervals for one year. Among these 342 children, 50.6 percent showed stable Pb-B, while 72.2 percent showed stable EP; d. e., the difference between the first and subsequent tests during the 12 month period did not exceed the 99 percent confidence limits for the methods of measurement. Overall, the trend in serial Pb-B nests was stable or could be explained clinically in 67 percent of the 342 children; similarly, trends in EP were stable or could be explained clinically in 91 percent of these same 342 children. It was concluded that EP tests are suitable as preliminary screening tests in children and that it is the more stable biologic test for monitoring children, provided that the factor of nutritional iron status is taken into account. Moreover contamination .is not a problem with micro EP tests.
Keywords
Hrčak ID:
167311
URI
Publication date:
6.4.1976.
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