Blood Lead Testing Among Children Enrolled in Medicaid

The Centers for Medicare and Medicaid Services (CMS) requires that all children enrolled in Medicaid or the Children’s Health Insurance Program (CHIP) receive blood lead tests at ages 12 and 24 months.1 Previous reports indicate that many children do not receive the required blood lead tests.2,3 Identifying factors associated with higher testing rates may support efforts to increase testing in this population. Using a national data set of US children enrolled in Medicaid, we calculated the proportion of children at the national and state level who received a blood lead test at ages 12 months and 24 months and by age 3 years, and we examined factors associated with testing.We selected a cohort of children enrolled in Medicaid and CHIP from 42 US states and Washington, DC from the CMS Transformed Medicaid Statistical Information System Analytic Files.4 We observed children for up to 3 years from January 2016 to December 2022 to assess blood lead testing at ages 12 months, 24 months, and at least once by 3 years. Testing was defined at each age as follows: 12 months of age (tested during 9–15 months of age), 24 months of age (tested during 21–27 months of age), and by 3 years (tested during 9–36 months of age).We calculated the percentage of children receiving a test at each age overall and stratified by child characteristics (including sex, race, ethnicity, region, urbanicity, living in a universal testing policy state, well-child visit status, and enrollment characteristics). Log-binomial regression was used to assess associations between testing and each of the following child characteristics: comprehensive managed care (CMC) enrollment, primary care case management (PCCM) enrollment, residing in a universal testing policy state, and having at least 1 well-child visit. We calculated risk ratios (RRs) and 95% CIs, adjusted for race, ethnicity, urbanicity, census region, CMC enrollment, PCCM enrollment, universal testing state, and well-child visit status. Detailed methodology is in the supplemental material (Supplementary Material A).Percentages of children receiving a blood lead test at ages 12 months, 24 months, and at least once by 3 years were 43%, 28%, and 63%, respectively (Table 1). Testing was highest among children identifying as non-Hispanic Asian and lowest among children identifying as non-Hispanic American Indian or Alaska Native (eg, 70% vs 34% at age 3 years, respectively). Testing was highest in the Northeast and South regions and lowest in the West (eg, 49% and 29% at age 12 months, respectively). Testing was lower in rural counties compared with metropolitan counties (eg, 55% vs 64% by age 3, respectively). Testing varied by US state with a range of 14% to 65% tested at age 12 months and 6% to 46% tested at age 24 months (Supplementary Table 2).In adjusted models, increased testing at age 12 months was associated with having 1 or more well-child visits (RR [95% CI]: 18.99 [18.78–19.21]), CMC plan enrollment (RR [95% CI]: 1.12 [1.12–1.13]), PCCM plan enrollment (RR [95% CI]: 1.20 [1.20–1.21]), and living in a universal testing policy state (RR [95% CI]: 1.02 [1.02–1.03]) (Table 2). Positive associations with these characteristics were also observed at ages 24 months and by 3 years. Additional results are in Supplementary Material B and Supplementary Tables 3 through 6.We found that less than half of eligible children received a Medicaid-required blood lead test at age 12 months, and less than one-third received a test at age 24 months, indicating gaps in early detection of lead exposure. CMS claims data only capture tests billed to Medicaid, and data quality and completeness varies by state; testing is likely underestimated in this analysis. Collaboration between Medicaid programs and health departments to improve data completeness and accuracy may enhance states’ ability to monitor adherence with testing requirements and target outreach appropriately. Our results highlight a strong, positive association between well-child visits and testing, suggesting opportunities to strengthen testing through engagement in preventive services. Tests among children outside of well-child visits may have occurred as part of diagnostic testing, rather than routine screening. Additional evaluation of policies, data systems, and preventive care access could help inform evidence-based strategies to improve testing among children enrolled in Medicaid.