LONGITUDINAL ASSESSMENT FOR LEAD-POISONING

In a previous study, we showed that in our region the prevalence of le ad poisoning (Pb greater than or equal to 10 mu g/dL [0.483 mu mol/L]) was high (29%) among urban infants, The objectives of this study were to assess the prevalence of lead poisoning over time in this cohort t o determine the best screening strategy, Eighty-nine percent (115/129) of infants who were initially screened for lead poisoning between 6 a nd 12 months of age had a repeat venous lead level by age 3 years (<(c hi)over bar>=19.8 months), The majority (70%) lived in a major city an d had private medical insurance (80%). The initial and repeat mean ven ous lead levels were similar for the overall population (lead(1) = 8.7 mu g/dL +/- 6.2 [0.420 +/- 0.299 mu mol/L] and leads = 7.7 mu g/dL +/ - 6.8 [0.371 +/- 0.328 mu mol/L]). However, the percentage of lead-poi soned (Ph greater than or equal to 10 mu g/dL or 0.483 mu mol/L) child ren whose levels were greater than or equal to 15 mu g/dL (0.724 mu mo l/L) increased from 28% to 48% on repeat, The utility of the initial s creen in predicting a second elevated lead level greater than or equal to 20 mu g/dL (0.966 mu mol/L) was as follows: sensitivity = 33%, spe cificity = 97%, positive predictive value = 40%, negative predictive v alue = 96%. We conclude that in this population, a single screen at 18 -24 months of age would reduce the need for multiple venipunctures and would detect those children in need of an intervention.