Lead Data

Testing of Childhood Blood Lead Levels in Allegheny County

*Before 2021, the threshold for elevated blood lead levels was 5 µg/dL

Allegheny County’s universal lead testing policy has led to approximately 5,000 more children being tested each year. In 2021, the Allegheny County Health Department lowered the threshold for elevated blood lead levels (EBLL) from 5 µg/dL to 3.5, allowing earlier intervention and monitoring for about 200 children annually. Between the implementation of universal testing in 2018 and the lowered threshold in 2021, the percent of children tested with an elevated blood lead level (5+ µg/dL) decreased steadily. Since that time, the percent has remained fairly consistent for those with levels above 5 µg/dL, but the percent of children with EBLL above 10 µg/dL continues to decrease. Currently, about 3.1% of children tested have an elevated blood lead level (3.5 µg/dL). 

Monitoring testing by week allows ACHD to identify seasonal trends and any possible irregularities in reporting to the system.  The most prominent trends observed are the increase in testing numbers leading up to the start of the school year (weeks 28-35) and the decrease in testing around holidays. In 2020, typical trends were not observed due to the COVID-19 pandemic, where the number of children tested decreased significantly starting at weeks 9 and 10 (March 2020). However, despite subsequent seasonal waves of COVID-19, 2020 trends were similar to 2019 for the remainder of the year. Since 2021, seasonal trends have remained relatively stable.

Monthly trends vary some from year to year, but August tends to be the month with the highest number of children tested.

The City of Pittsburgh has consistently had a higher rate of children tested with a confirmed elevated result compared to the County as a whole. In 2020, 3,411 per 100,000 children (3.4%) tested who lived in the City of Pittsburgh had a confirmed elevated lead level compared to 1,675 per 100,000 (1.7%) of all Allegheny County children tested.

Exposure to lead through contaminated paint is a significant risk in Allegheny County and may explain some of this disparity. Lead paint was banned for consumer use in 1978, houses built prior to this are at an increased likelihood of containing lead-based paint.  The older the home the higher the likelihood of containing lead-based paint. In the city of Pittsburgh an estimated 59.6% of housing units were built before 1950 compared to 39.1% of all county housing units. A higher percentage of homes built prior to the banning of lead paint can translate to an increased risk of exposure for children living in this area.

See Housing Built Before 1980 and Housing Built Before 1950 in the Maps and Testing Data section.

Allegheny County’s universal testing policy requires a child’s first test to be completed between 9-12 months of age. According to Pennsylvania’s age range requirements for screening visits, 412 days is the maximum age to complete the 1 year screening visit. The percent of Allegheny County children who received testing for lead by the age of 412 days has increased since 2014. Of all Allegheny County children tested in 2023, 37.9% were under the age of 1.

Testing Story Map

View the above Story Map on the ARCGIS website

Testing Data

• Aggregated Percent of Children Tested with Elevated Blood Lead Levels by Census Tract, 2017 – 2021(PDF, 200KB)
• Aggregated Percent of Children Tested with Elevated Blood Lead Levels by Municipality and Neighborhood, 2017 – 2021(PDF, 162KB)
• Aggregated Percent of Children Tested with Elevated Blood Lead Levels by School District, 2017 – 2021(PDF, 108KB)

Additional Data

• Allegheny County Priority Lead Risk Factor and Elevated Blood Lead Level Areas by Census Tract (Map)(PDF, 972KB)
• Housing Built Before 1950(PDF, 4MB)
• Housing Built Before 1980(PDF, 4MB)

• December 2017 Lead Task Force Final Report and Recommendations
• September 2018 Inaugural Allegheny County Lead Report
• December 2022 Allegheny County Lead Report

≥3.5 µg/dL – This represents a measurement of greater than or equal to 3.5 micrograms of lead per deciliter of blood. The Health Department currently treats blood lead level tests of 3.5 µg/dL or more as elevated. This measurement is based on the Centers for Disease Control and Prevention’s definition, which was increased in 2021. Before that, the threshold was 5 µg/dL. Some documents with historical data still use that as a reference.

Capillary test – A capillary test is when blood is drawn by a finger-stick. The results are available within a couple of minutes. However, sometimes capillary tests can give incorrectly high results due to lead on the skin or in the environment. Because of this, a high capillary test should be confirmed by a venous test. A low/negative test does not require confirmation.

Venous test – A venous test is when blood is drawn from a vein in the arm. This is typically done to confirm a previous capillary test result and needs to be prescribed by a doctor. Some doctors will request a venous test without an initial capillary test.

Elevated capillary without follow up – If an initial capillary test was elevated but no venous test was done to confirm the result, it is considered an elevated capillary without follow up. The Health Department encourages providers to make sure follow up venous tests are performed in a timely manner.

Confirmed elevated blood lead level – The Health Department recognizes venous blood lead tests with a result of ≥3.5 µg/dL as a confirmed elevated case. Because one child may have received several tests, the highest venous test result is used as the final value.

Percent confirmed elevated (children with a confirmed elevated test / all children tested) - The percent of elevated blood lead levels that the Health Department follows is the number of individual children with confirmed elevated tests (only blood venous tests count as confirmed tests) divided by the number of individual children tested. For county-wide stratified data (3.5-4.9 µg/dL, 5 – 9.9 µg/dL, 10 + µg/dL), a child’s highest confirmed value is used. Measurements are not affected by multiple elevated blood tests for a single child in a single period.

Children (study population)– Lead surveillance is focused on children under age six years, in alignment with state and national surveillance standards. Lead is particularly toxic to the developing brain, and the hand-to-mouth habits of young children put them at increased risk of ingestion from contaminated sources. 

Data accuracy is dependent upon laboratory reporting – The accuracy of blood test results for lead reported to the Health Department is dependent on the laboratory conducting the tests and reporting the results. Different laboratories use different instruments to test blood samples.  

We are aware of the 2021 recall of Magellan LeadCare® Blood Lead Tests. These devices are no longer being used, but may affect some of the data collected before 2021. Most of the affected devices were in use between 2013-2017, before Allegheny County implemented universal testing. There is no risk to those who were tested by these devices except those associated with incorrect results (false negatives, possible lack of appropriate follow up). If you suspect your child may have received incorrect results, ask your doctor about retesting.

Possible biases in those who are getting tested – Mandatory lead testing for children was implemented in Allegheny County on January 1, 2018. Children voluntarily tested for lead before that date may have received a blood test for a specific reason. This means that community data before 2018 may not be fully representative of the total population. Also, while testing is currently mandatory, there are still some children who are not being tested. The Health Department continues to work with providers throughout the county, and to explore new ways of reaching out to families in the community.

Technical Resources

• Health Note(PDF, 420KB)
• PA NEDSS, ACHD & You(PDF, 253KB)
• ACHD Lead Data Technical Changes Timeline(PDF, 109KB)