Test Summary
Lead (Venous)
Test code: 599
Clinical use
- Detect lead exposure and/or toxicity
- Monitor lead detoxification
Clinical background
Lead is a highly toxic metal that may be ingested, inhaled, or absorbed directly through the skin. Toxic effects are categorized as gastrointestinal, central nervous system, neuromuscular, hematologic, renal, or constitutional. Common symptoms include constipation, anorexia, abdominal pain, weight loss, fatigue, and characteristic peripheral neuropathy (wrist drop). Severe poisoning may result in nephropathy, encephalopathy, convulsions, and even death.
Lead poisoning may occur after exposure to leaded containers, lead clay, glazed pottery, lead solder, paints, or bullets (wound) or through occupational exposure (eg, mining, smelters, sheet metal, battery manufacture, automobile radiator repair, demolition work, alloys, or metal plating). Family members may also be exposed to lead if employees inadvertently bring lead home on clothes or in cars.
Infants and children aged 9 months to 6 years are particularly susceptible to the effects of lead due to hand-to-mouth oral behaviors, greater gastrointestinal absorption, and a breathing zone closer to contaminated ground surfaces. Lead exposure can lead to irreversible IQ deficits, poor academic achievement, reduced attention span, and hyperactivity. Children at increased risk for lead exposure include immigrants, refugees, international adoptees, and those who live in homes built before 1978 or communities with a high prevalence (≥25%) of homes built before 1960.1
The Centers for Disease Control and Prevention (CDC) advises that a blood lead reference value of 3.5 μg/dL be used to identify children who have more lead in their blood than 97.5% of US children.2 These children are at increased risk for lead exposure and its negative health consequences.2
Although both venous and capillary blood specimens can be used to screen for lead exposure, venous blood provides more accurate measurements.3 Given the potential for lead contamination of the skin, guidelines recommend that elevated blood lead levels measured in capillary blood specimens be confirmed with measurement in venous blood.3,4
Guidance for screening children for lead poisoning varies among professional organizations. Whereas some recommend universal screening at ages 12 and 24 months, others recommend screening only children at increased risk, yet others find insufficient evidence to support screening any asymptomatic children, even those at increased risk.4 Guidance similarly varies for pregnant and lactating women.4
Quest Diagnostics offers Lead (Venous) (test code 599) for screening and monitoring at-risk children, men, and women, including women who are pregnant, lactating, or both. No safe blood level in children has been identified. The reference range for adults and children is now <3.5 μg/dL. According to the CDC and the American Academy of Pediatrics (AAP), any finding of lead in the blood requires follow-up, which varies according to level.1,3 A blood lead level of ≥3.5 μg/dL triggers increased monitoring.3 For screening, Quest also offers Lead, Capillary (test code 39027); however, elevated blood lead level identified by this test should be confirmed with a venous specimen.3,4 For assessing occupational lead exposure, consider Lead (Venous), OSHA (test code 3058).
Individuals suitable for testing
- Individuals with signs or symptoms of lead poisoning
- Individuals and their family members exposed to lead through their occupation or hobbies
- Infants, children, and pregnant or lactating women at an increased risk for lead exposure or who need follow-up testing according to CDC and the American College of Obstetricians and Gynecologists recommendations (Tables 1-3)
- Newly arrived refugees and immigrants (children, infants, adolescents, and pregnant or lactating women) and internationally adopted children
Method
- Inductively coupled plasma/mass spectrometry (ICP/MS)
- Instrument calibrations performed with standards provided by the National Institutes of Standards and Technology (NIST)
- Analytical measurement range: 0.5 μg/dL to 100.0 μg/dL
Interpretive information
For children and pregnant or lactating women, follow-up depends on the blood lead level (Tables 1-3). Levels <0.5 μg/dL are below detection limits.
Table 1. CDC-recommended Confirmatory and Follow-up Testing for Various Venous Blood Lead Levels (BLL) in Children
Blood lead3,a |
Confirmatory testing3,b |
Follow-up blood testing3,a |
<3.5 μg/dL |
Not needed |
BLL testing at ages 12 months and 24 months in children enrolled in Medicaid who have been previously screened or at ages 24-72 months in children who have not been screened
|
3.5-9 μg/dL |
Within 3 months |
BLL testing in 3 months and then in 6-9 months as BLL decline (eg, after possible environmental remediation)
|
10-19 μg/dL |
Within 1 month |
BLL testing in 1-3 months and then in 3-6 months as BLL decline (eg, after possible environmental remediation)
|
20-44 μg/dL |
Within 2 weeks |
BLL testing in 2 weeks-1 month and then in 1-3 months as BLL decline (eg, after possible environmental remediation)
|
≥45 μg/dL |
Within 48 hours |
BLL testing as soon as possible |
| a | Changes in BLL owing to changes in seasonal weather may be more apparent in areas with colder climates. Increased exposure in the summer months may require more frequent follow-ups. |
| b | Confirmatory testing in venous blood is needed when elevated blood lead levels are initially measured in capillary blood. |
Table 2. CDC-recommended Follow-up Testing for Various Venous Blood Lead Levels (BLL) in Pregnant Women
Blood lead5,6 |
Follow-up blood testing (maternal or umbilical cord BLL at delivery)5,6 |
<5 μg/dL |
None |
5-14 μg/dL |
BLL testing within 1 month |
15-24 μg/dL |
BLL testing within 1 month and then every 2-3 months, or more frequently based on risk factors |
25-44 μg/dL |
BLL testing within 1-4 weeks and then every month |
≥45 μg/dL |
BLL testing within 24 hours and then at frequent intervals depending on clinical interventions |
Table 3. CDC-recommended Follow-up Testing for Various Venous Blood Lead Levels (BLL) in Womena During Breastfeeding
| Blood lead6,a | Follow-up blood testing6,a |
<5 μg/dL |
None |
5-19 μg/dL |
BLL testing every 3 months or more frequently if infant BLL are steady or rising |
20-39 μg/dL |
BLL testing 2 weeks postpartum and then at 1-3 month intervals depending on infant BLL |
≥40 μg/dL |
BLL testing within 24 hours and then at frequent intervals depending on clinical interventions (do not initiate breastfeeding until BLL decline to <40 μg/dL) |
| a | For women who become pregnant while breastfeeding, follow schedule for pregnancy. |
This information is provided for educational purposes only and is not intended as medical advice. A physician’s test selection and interpretation, diagnosis, and patient management decisions should be based on their education, clinical expertise, and assessment of the patient.
References
- Council on Environmental Health. Prevention of childhood lead toxicity. Pediatrics. 2016;138(1):e20161493. doi:10.1542/peds.2016-1493
- Ruckart PZ, Jones RL, Courtney JG, et al. Update of the blood lead reference value — United States, 2021. Morb Mortal Wkly Rep. 2021;70(43):1509-1512. doi:10.15585/mmwr.mm7043a4
- Recommended actions based on blood lead level. Centers for Disease Control and Prevention. Updated August 21, 2025. Accessed May 18, 2026. https://www.cdc.gov/lead-prevention/hcp/clinical-guidance/index.html
- US Preventive Services Task Force. Screening for elevated blood lead levels in children and pregnant women: US Preventive Services Task Force recommendation statement. JAMA. 2019;321(15):1502-1509. doi:10.1001/jama.2019.3326
- Committee on Obstetric Practice. Committee Opinion No. 533: lead screening during pregnancy and lactation. Obstet Gynecol. 2012;120(2, Part 1):416-420. doi:10.1097/aog.0b013e31826804e8
- Centers for Disease Control and Prevention. Guidelines for the identification and management of lead exposure in pregnant and lactating women. US Department of Health and Human Services; 2010. Accessed May 18, 2026. https://www.cdc.gov/lead-prevention/media/pdfs/2025/03/cdc_147837_DS1.pdf
Content reviewed 7/2026
39027 - Lead, Capillary
599 - Lead (Venous)
Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.
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