Lead toxicity

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Last reviewed: 8 Sep 2025

Last updated: 09 Jun 2023

Lead toxicity occurs after occupational or home exposure to lead. There is no threshold level for toxicity.

Anyone at risk of lead exposure requires screening with regular blood lead measurements. There is no "normal" level, and interventions are initiated at the first sign of increased exposure.

Lead toxicity causes neurodevelopmental dysfunction in children and a range of cardiovascular, renal, neurologic, and hematologic dysfunctions in adults.

The mainstay of treatment is removal of the source. Chelation therapy is given for blood levels ≥45 micrograms/dL in a child or >70 micrograms/dL in an adult, or if the patient is symptomatic.

Acute lead encephalopathy is a medical emergency requiring aggressive chelation therapy in an intensive care setting.

Acute symptoms resolve with treatment, but neurologic impairments and cardiovascular toxicities are irreversible.

Lead resides in bone for decades after exposure has ceased; all patients require long-term monitoring.

Definition

Lead toxicity is a multisystem disease produced by inhalation or ingestion of lead. It produces neurodevelopmental dysfunction in children and a range of cardiovascular, renal, neurologic, and hematologic dysfunctions in adults. Any detectable lead level is consistent with exposure to lead.

The US Centers for Disease Control and Prevention (CDC) employs a blood lead reference value of ≥3.5 micrograms/dL to identify children with blood lead levels greater than most other children’s levels.[1] A case definition for an elevated blood lead level in an adult (person ≥16 years of age) is ≥5 micrograms/dL.[2][3] In an adult, the US Occupational Safety and Health Administration considers a blood lead level of ≥25 micrograms/dL to be serious, requiring inspection.[2]

History and exam

Key diagnostic factors

family history of lead poisoning or parental work with lead
cognitive impairment (children)
behavioral changes (children)
headaches (children)
clumsiness and agitation (children)
loss of appetite (children)
constipation (children)
somnolence (children)
altered mental state
cerebellar signs
seizures
coma

Full details

Other diagnostic factors

colicky abdominal pain (adults)
hypertension (adults)

Full details

Risk factors

age 9 to 36 months
housing with lead hazards
occupational lead exposure
lead-contaminated water supplies
low socioeconomic status
hobbies working with lead
pica
use of folk medications
fetal exposure
mineral-deficient and high-fat diets
bullet firing ranges

Full details

Diagnostic tests

1st tests to order

whole-blood lead level
complete blood count
serum ferritin

Full details

Tests to avoid

post-chelator challenge urinary metal testing
hair or nail testing
heavy metal screening test

Full details

Tests to consider

24-hour urine lead with chelation
abdominal radiographs
nerve conduction studies

Full details

Treatment algorithm

ACUTE

all patients

Contributors

Authors

J. Routt Reigart, MD

Professor Emeritus of Pediatrics

Medical University of South Carolina

Charleston

Disclosures

JRR declares that he has no competing interests.

Peer reviewers

Howard Hu, MD, MPH, ScD

NSF International Chair

Department of Environmental Health Sciences

Professor of Environmental Health Sciences, Epidemiology and Internal Medicine

University of Michigan Schools of Public Health and Medicine

Ann Arbor

Disclosures

HH is an author of a reference cited in this topic. HH has received research funding greater than 6 figures USD.

Rose H. Goldman, MD, MPH

Chief

Occupational & Environmental Medicine

Cambridge Health Alliance

Associate Professor of Medicine

Harvard Medical School

Associate Professor of Environmental Health Sciences

Harvard School of Public Health

Boston

Disclosures

None disclosed.

Alison Jones, MD, FRCPE, FiBIOL, FRCP, FRACP

Dean

School of Medicine

Campbelltown Campus

University of Western Sydney

Australia

Disclosures

AJ declares that she has no competing interests.

Peer reviewer acknowledgements

BMJ Best Practice topics are updated on a rolling basis in line with developments in evidence and guidance. The peer reviewers listed here have reviewed the content at least once during the history of the topic.

Disclosures

Peer reviewer affiliations and disclosures pertain to the time of the review.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

Centers for Disease Control and Prevention (CDC). Understanding blood lead levels. Adult Blood Lead Epidemiology and Surveillance (ABLES). National Institute for Occupational Safety and Health (NIOSH) workplace safety & health topics. Apr 2023 [internet publication].Full text

Centers for Disease Control and Prevention (CDC). Blood lead levels: United States, 1988-1991. MMWR Morb Mortal Wkly Rep. 1994;43:545-548.Full text Abstract

Harvey B, ed. Managing elevated blood lead levels among young children: recommendations from the Advisory Committee on Childhood Lead Poisoning Prevention. Atlanta, GA: CDC; 2002.Full text

Centers for Disease Control and Prevention (CDC). Adult blood lead epidemiology and surveillance - United States, 2008-2009. MMWR Morb Mortal Wkly Rep. 2011 Jul 1;60(25):841-5.Full text Abstract

Mahaffey KR. Nutrition and lead: strategies for public health. Environ Health Perspect. 1995;103(suppl 6):191S-196S.Full text Abstract

Nussbaumer-Streit B, Mayr V, Dobrescu AI, et al. Household interventions for secondary prevention of domestic lead exposure in children. Cochrane Database Syst Rev. 2020 Oct 6;10:CD006047.Full text Abstract

Yeoh B, Woolfenden S, Lanphear B, et al. Household interventions for preventing domestic lead exposure in children. Cochrane Database Syst Rev. 2014;(12):CD006047.Full text Abstract

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials
- Iron deficiency anemia
- Non-lead peripheral neuropathy
- Arsenic poisoning
More Differentials
Guidelines
- Childhood lead poisoning prevention
- WHO guideline for clinical management of exposure to lead
More Guidelines
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Lead toxicity

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic tests

1st tests to order

Tests to avoid

Tests to consider

Treatment algorithm

all patients

Contributors

Authors

J. Routt Reigart, MD

Disclosures

Peer reviewers

Howard Hu, MD, MPH, ScD

Disclosures

Rose H. Goldman, MD, MPH

Disclosures

Alison Jones, MD, FRCPE, FiBIOL, FRCP, FRACP

Disclosures

Peer reviewer acknowledgements

Disclosures

References

Key articles

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials

Guidelines

Log in or subscribe to access all of BMJ Best Practice

Log in or subscribe to access all of BMJ Best Practice

Log in to access all of BMJ Best Practice