ENVIRONMENTAL HEALTH
Public Health Laboratories : Preventing Lead Poisoning Then and Now
By Paul Allwood , PhD , MPH , Lead Poisoning Prevention and Surveillance Branch , US Centers for Disease Control and Prevention ; Jennifer Liebreich , MPH , manager , Environmental Health ; and Perri Zeitz Ruckart , DrPH , MPH , Lead Poisoning Prevention and Surveillance Branch , US Centers for Disease Control and Prevention
There are no safe blood lead levels ( BLL ) in children . Even low levels of lead in blood can cause developmental delays and behavioral issues . Since 1991 , the US Centers for Disease Control and Prevention ’ s ( CDC ’ s ) Childhood Lead Poisoning Prevention Program ( CLPPP ) has supported state and local health departments to protect children from lead exposure and its harmful effects . Doctors ’ offices often test children ’ s blood for lead using point-of-care devices , such as LeadCare . Public health laboratories use instrument platforms such as inductively coupled plasma / mass spectrometry ( ICP-MS ) and graphite furnace atomic absorption spectroscopy ( GFAAS ) to provide more accurate ( e . g ., lower detection and reporting limits ) and confirmatory testing .
Complexities of Lead Testing
Currently , lead testing capabilities include point-of-care or definitive laboratory tests . Point-of-care tests may offer immediate results during a patient ’ s visit but are approved for use on capillary specimens only . Laboratory tests using either GFAAS or ICP-MS provide the most sensitive and accurate tests results . At lower detection limits , steps must be taken to minimize contamination during specimen collection and analysis .
Role of Laboratories in Lead Poisoning Prevention
CLPPP and state and local public health laboratories have played a major role in blood lead testing . Building upon the work of multiple long-standing state programs , state public health laboratories are able to leverage lead testing capacity and capabilities through the Laboratory Response Network for Chemical Threats ( LRN-C ), a national network of CDC and local and state public health laboratories prepared to respond to chemical terrorism and other public health emergencies . Some LRN-C laboratories are qualified to perform the LRN-C blood metals panel , which includes lead .
In 2023 , APHL ’ s Pediatric Lead Testing Capability and Capacity Survey assessed the current extent of public health laboratory involvement in lead testing and desire to develop or expand childhood lead testing programs if funds were available . Of the 70 ( 63 % response rate ) public health laboratories responding to the survey :
• 36 % conduct routine analyses of pediatric lead testing
• 7 % perform such analyses only in emergency situations
• One laboratory provides a reference laboratory service
Public health laboratories currently capable of blood lead testing indicated that their laboratories have the capacity to provide additional analyses for their pediatric lead testing program if more resources were made available .
Since CDC lowered the blood lead reference value ( BLRV ) from 5.0 to 3.5 micrograms per deciliter (µ g / dL ) in 2021 , the survey included a question about resultant changes to analytical practices . The survey examined the average detection and reporting limits for a variety of testing platforms and how the reported limits compare to the BLRV . In response to the updated BLRV :
• 26 % of respondent state laboratories made changes to their contamination control practices
• 53 % enhanced communication with collaborators like public health partners and clinicians
Collaboration Is Key to Success
Recent events highlight the importance of environmental health system collaboration to prevent lead exposure . In fall 2023 , a nationwide lead contamination investigation began when the North Carolina Department of
Health and Human Services ( NCDHHS ) CLPPP identified four children with high blood lead levels due to contaminated applesauce pouches . The investigation included collaboration with the local health departments , NC State Laboratory of Public Health , and the North Carolina Department of Agriculture & Consumer Services to determine the route of exposure .
NCDHHS identified apple puree pouches as a potential source of exposure and reported that to the US Food and Drug Administration ( FDA ). FDA ’ s Laboratory Flexible Funding Model ( LFFM ) laboratories — who support an integrated food safety system by testing human and animal food and are also APHL members — swiftly collected samples and conducted testing across the country . Lead chromate found in the cinnamon of these products was identified as the source of contamination . The collaborative investigation by CDC , FDA , and state and local government agencies resulted in a national recall , demonstrating the impact of laboratory and public health partnerships .
Looking Toward the Future
The BLRV has declined as BLLs in American children decreased . If the BLRV is lowered further , quality laboratory practices , contamination controls , and highly accurate testing methods and instrumentation are expected to rise in importance for achieving accurate test results . The existing relationships between public health laboratories and environmental health system partners provide an inimitable web of preparedness to potentially expand pediatric lead testing efforts and prevent lead poisoning . g
Disclaimer : The content and conclusions in these presentations are those of the authors and presenters and do not necessarily represent the views of , nor should any endorsements be inferred by , the US Centers for Disease Control and Prevention .
Reference : CLSI . Measurement Procedures for the Determination of Lead in Whole Blood . 3rd ed . CLSI guideline C40 . Clinical and Laboratory Standards Institute ; 2024 .
24 LAB MATTERS Fall 2024
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