Lead (Venous)
Lead (Venous)
This test is used for screening and monitoring for lead exposure and toxicity.
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 a characteristic peripheral neuropathy (wrist drop). Severe poisoning may lead to nephropathy, encephalopathy, convulsions, and even death.
Lead poisoning may occur after exposure to leaded containers, lead clay, glazed pottery, lead solder, paints, bullets (wound) or through occupational exposure (mining, smelters, sheet metal, battery manufacture, automobile radiator repair, demolition work, alloys, and metal plating). Workers' family members may also be exposed to lead contamination brought 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, and international adoptees, as well as children who live in poorly or recently repaired homes built before 1960 or communities with a high prevalence (≥25%) of homes built before 1960.
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.1 These children are at increased risk for lead exposure and its negative health consequences.1
Although both venous and capillary blood specimens can be used to screen for lead exposure, venous blood provides more accurate measurements.2 Given the potential for lead contamination of the skin,2 guidelines recommend that elevated blood lead levels measured in capillary blood specimens be confirmed with measurement in venous blood.2,3
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 and 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 requires follow-up, which varies according to level. 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 test results should be confirmed with a venous specimen.
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
- Children aged 12 and 24 months (in an area of high prevalence area or on Medicaid)
- Children or pregnant or lactating women at increased risk for lead exposure
- Newly arrived refugees and immigrants (children, infants, adolescents, pregnant and lactating women) and internationally adopted children
Method
- Inductively coupled plasma/mass spectrometry (ICP/MS)
- Instrument calibrations performed with standards traceable to the National Institutes of Standards and Technology (NIST)
- Analytical measurement range: 1 μg/dL to 100 μg/dL
- Accuracy within ±4 μg/dL (±10% relative) of CDC accuracy standards (±2 μg/dL below 10 μg/dL)
Interpretive information
For children and pregnant and lactating women, follow-up depends on the blood lead level (Tables 1-3). Levels <1 μg/dL are below detection limits.
Table 1. CDC-Recommended Follow-up Testing for Various Venous Blood Lead Levels (BLL) in Children
Blood lead3,a |
Follow-up blood testing3,a |
<3.5 μg/dL |
BLL testing at ages 12 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 |
BLL testing in 3 months and then 6-9 months as BLL decline (eg, after possible environmental remediation)
|
10-19 μg/dL |
BLL testing 1-3 months and then 3-6 months as BLL decline (eg, after possible environmental remediation )
|
20-44 μg/dL |
BLL testing in 2 weeks-1 month and then 1-3 months as BLL decline (eg, after possible environmental remediation )
|
≥45 μg/dL |
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. |
Table 2. CDC-Recommended Follow-up Testing for Various Venous Blood Lead Levels (BLL) in Pregnant Women
Blood lead6,7 |
Follow-up blood testing (maternal or umbilical cord BLL at delivery)6,7 |
<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 lead6,7,a | Follow-up blood testing6,7,a |
<5 μg/dL |
None |
5-19 μg/dL |
BLL testing every 3 months, 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
- Ruckart PZ, Jones RL, Courtney JG, et al. Update of the blood lead reference value - United States, 2021. MMWR Morb Mortal Wkly Rep. 2021;70(43):1509-1512. doi:10.15585/mmwr.mm7043a4
- Centers for Disease Control and Prevention Advisory Committee on Childhood Lead Poisoning Prevention. Interpreting and managing blood lead levels < 10 μg/dL in children and reducing childhood exposures to lead: recommendations of CDC's Advisory Committee on Childhood Lead Poisoning Prevention. MMWR Recomm Rep. 2007;56 (RR-8):1-16.
- Recommended actions based on blood lead level. Centers for Disease Control and Prevention. Updated December 2, 2022. Accessed February 20, 2023. https://www.cdc.gov/nceh/lead/advisory/acclpp/actions-blls.htm
- 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
- Health CoE, Lanphear BP, Lowry JA, et al. Prevention of childhood lead toxicity. Pediatrics. 2016;138(1):e20161493. doi:10.1542/peds.2016-1493
- Committee on Obstetric Practice. Committee opinion No. 533: lead screening during pregnancy and lactation. Obstet Gynecol. 2012;120 (2 Pt 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 February 21, 2023. https://www.cdc.gov/nceh/lead/docs/publications/leadandpregnancy2010.pdf.
Content reviewed 02/2023
This test is used for screening and monitoring for lead exposure and toxicity.
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 a characteristic peripheral neuropathy (wrist drop). Severe poisoning may lead to nephropathy, encephalopathy, convulsions, and even death.
Lead poisoning may occur after exposure to leaded containers, lead clay, glazed pottery, lead solder, paints, bullets (wound) or through occupational exposure (mining, smelters, sheet metal, battery manufacture, automobile radiator repair, demolition work, alloys, and metal plating). Workers' family members may also be exposed to lead contamination brought 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, and international adoptees, as well as children who live in poorly or recently repaired homes built before 1960 or communities with a high prevalence (≥25%) of homes built before 1960.
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.1 These children are at increased risk for lead exposure and its negative health consequences.1
Although both venous and capillary blood specimens can be used to screen for lead exposure, venous blood provides more accurate measurements.2 Given the potential for lead contamination of the skin,2 guidelines recommend that elevated blood lead levels measured in capillary blood specimens be confirmed with measurement in venous blood.2,3
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 and 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 requires follow-up, which varies according to level. 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 test results should be confirmed with a venous specimen.
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
- Children aged 12 and 24 months (in an area of high prevalence area or on Medicaid)
- Children or pregnant or lactating women at increased risk for lead exposure
- Newly arrived refugees and immigrants (children, infants, adolescents, pregnant and lactating women) and internationally adopted children
Method
- Inductively coupled plasma/mass spectrometry (ICP/MS)
- Instrument calibrations performed with standards traceable to the National Institutes of Standards and Technology (NIST)
- Analytical measurement range: 1 μg/dL to 100 μg/dL
- Accuracy within ±4 μg/dL (±10% relative) of CDC accuracy standards (±2 μg/dL below 10 μg/dL)
Interpretive information
For children and pregnant and lactating women, follow-up depends on the blood lead level (Tables 1-3). Levels <1 μg/dL are below detection limits.
Table 1. CDC-Recommended Follow-up Testing for Various Venous Blood Lead Levels (BLL) in Children
Blood lead3,a |
Follow-up blood testing3,a |
<3.5 μg/dL |
BLL testing at ages 12 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 |
BLL testing in 3 months and then 6-9 months as BLL decline (eg, after possible environmental remediation)
|
10-19 μg/dL |
BLL testing 1-3 months and then 3-6 months as BLL decline (eg, after possible environmental remediation )
|
20-44 μg/dL |
BLL testing in 2 weeks-1 month and then 1-3 months as BLL decline (eg, after possible environmental remediation )
|
≥45 μg/dL |
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. |
Table 2. CDC-Recommended Follow-up Testing for Various Venous Blood Lead Levels (BLL) in Pregnant Women
Blood lead6,7 |
Follow-up blood testing (maternal or umbilical cord BLL at delivery)6,7 |
<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 lead6,7,a | Follow-up blood testing6,7,a |
<5 μg/dL |
None |
5-19 μg/dL |
BLL testing every 3 months, 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
- Ruckart PZ, Jones RL, Courtney JG, et al. Update of the blood lead reference value - United States, 2021. MMWR Morb Mortal Wkly Rep. 2021;70(43):1509-1512. doi:10.15585/mmwr.mm7043a4
- Centers for Disease Control and Prevention Advisory Committee on Childhood Lead Poisoning Prevention. Interpreting and managing blood lead levels < 10 μg/dL in children and reducing childhood exposures to lead: recommendations of CDC's Advisory Committee on Childhood Lead Poisoning Prevention. MMWR Recomm Rep. 2007;56 (RR-8):1-16.
- Recommended actions based on blood lead level. Centers for Disease Control and Prevention. Updated December 2, 2022. Accessed February 20, 2023. https://www.cdc.gov/nceh/lead/advisory/acclpp/actions-blls.htm
- 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
- Health CoE, Lanphear BP, Lowry JA, et al. Prevention of childhood lead toxicity. Pediatrics. 2016;138(1):e20161493. doi:10.1542/peds.2016-1493
- Committee on Obstetric Practice. Committee opinion No. 533: lead screening during pregnancy and lactation. Obstet Gynecol. 2012;120 (2 Pt 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 February 21, 2023. https://www.cdc.gov/nceh/lead/docs/publications/leadandpregnancy2010.pdf.
Content reviewed 02/2023