Patterns of Children’s Blood Lead Screening and Blood Lead Levels in North Carolina, 2011–2018—Who Is Tested, Who Is Missed?

BACKGROUND: No safe level of lead in blood has been identified. Blood lead testing is required for children on Medicaid, but it is at the discretion of providers and parents for others. Elevated blood lead levels (EBLLs) cannot be identified in children who are not tested. OBJECTIVES: The aims of this research were to identify determinants of lead testing and EBLLs among North Carolina children and estimate the number of additional children with EBLLs among those not tested. METHODS: We linked geocoded North Carolina birth certificates from 2011–2016 to 2010 U.S. Census data and North Carolina blood lead test results from 2011–2018. We estimated the probability of being screened for lead and created inverse probability (IP) of testing weights. We evaluated the risk of an EBLL of [Formula: see text] at [Formula: see text] of age, conditional on characteristics at birth, using generalized linear models and then applied IP weights to account for missing blood lead results among unscreened children. We estimated the number of additional children with EBLLs of all North Carolina children using the IP-weighted population and bootstrapping to produce 95% credible intervals (CrI). RESULTS: Mothers of the 63.5% of children (402,002 of 633,159) linked to a blood lead test result were disproportionately young, Hispanic, Black, American Indian, or on Medicaid. In full models, maternal age [Formula: see text] [[Formula: see text]; 95% confidence interval (CI): 1.13, 1.20] or smoking ([Formula: see text] 1.14; 95% CI: 1.12, 1.17); proximity to a major roadway ([Formula: see text] 1.10; 95% CI: 1.05, 1.15); proximity to a lead-releasing Toxics Release Inventory site ([Formula: see text] 1.08; 95% CI: 1.03, 1.14) or a National Emissions Inventory site ([Formula: see text] 1.11; 95% CI: 1.07, 1.14); and living in neighborhoods with more housing built before 1950 ([Formula: see text] 1.10; 95% CI: 1.05, 1.14) or before 1940 ([Formula: see text] 1.18; 95% CI: 1.11, 1.25) or more vacant housing ([Formula: see text] 1.14; 95% CI: 1.11, 1.17) were associated with an increased risk of EBLL, whereas overlap with a public water service system was associated with a decreased risk of EBLL ([Formula: see text] 0.85; 95% CI: 0.83, 0.87). Children of Black mothers were no more likely than children of White mothers to have EBLLs ([Formula: see text] 0.98; 95% CI: 0.96, 1.01). Complete blood lead screening in 2011–2018 may have identified an additional 17,543 (95% CrI: 17,462, 17,650) children with EBLLs [Formula: see text]. DISCUSSION: Our results indicate that current North Carolina lead screening strategies fail to identify over 30% (17,543 of 57,398) of children with subclinical lead poisoning and that accounting for characteristics at birth alters the conclusions about racial disparities in children’s EBLLs. https://doi.org/10.1289/EHP10335