About the Test
Purpose of the test
The blood lead test is used to screen for exposure to lead. It may also be ordered to monitor the effectiveness of treatment and to confirm lead levels are decreasing over time.
What does the test measure?
The lead test is used to determine the concentration of lead in the whole blood at the time the sample was collected.
Lead concentrations are monitored at the local level following state and national standards. Centers for Disease Control and Prevention (CDC), the American Academy of Pediatrics (AAP), and a variety of other organizations make recommendations regarding screening children for lead exposure.
Blood lead is monitored in workers whose environment contains lead. It is used to evaluate chronic and recent lead exposure. Sometimes, a zinc protoporphyrin (ZPP) test is also ordered.
The ZPP is increased when lead begins to affect red blood cell production. It is not sensitive enough to use as a screening tool for children, but it may be ordered to help evaluate average lead exposure in adults over the last several weeks. ZPP may also be ordered when you show signs of lead toxicity, but your blood lead level (BLL) is not increased to a level to account for these symptoms.
When should I get this test?
For screening children:
The AAP recommends that a risk assessment be performed for lead exposure at well-child visits at six, nine, 12, 18, and 24 months, and at 3, 4, 5, and 6 years of age. A BLL test should only be done if the risk assessment returns positive.
According to the AAP and CDC, universal screening or BLL tests are no longer recommended, except for in high prevalence areas where more than 12% of children between 1-2 years of age have an elevated BLL, or where more than 27% of housing was built before the 1950s.
Pediatricians may also offer screening to:
- Medicaid-eligible children at 1 and 2 years of age
- At the earliest opportunity for children of all ages who are recent immigrants, refugees, or adoptees
- A child whose parent, guardian, or provider requests blood lead testing due to suspected exposure
Check with your health care practitioner and/or local health department regarding lead screening guidelines specific to the risks in your area.
Managing children with elevated blood levels:
Since fingerstick samples can be contaminated during specimen collection, an initial elevated result obtained by a fingerstick should be repeated with testing on a blood sample drawn from a vein in the arm for confirmation. And time to repeat varies based on the BLL measured. Follow-up testing is then used to monitor the persistence of an elevated blood lead test and is recommended whenever a child’s BLL is higher than 5 micrograms per deciliter (5 mcg/dL).
For screening adults:
- Blood lead tests may be ordered to screen adults in the workplace when lead contamination is possible. Family members also may be screened because lead can be carried home on clothing. This testing conforms to federal and state laws for occupational exposure.
- Adults with hobbies involving lead-based paints, ceramics, or gasoline should also be tested.
- Pregnant women and mothers who are breastfeeding may be screened if they are at increased risk of lead exposure.
For children and adults, lead testing may be ordered when signs and symptoms suggest potential lead poisoning. These symptoms are non-specific and may include:
- Changes in mood and/or cognitive ability
- Nausea, prolonged stomach distress
- Abdominal pain, constipation
- Weight loss
- Peripheral neuropathy, which is tingling, numbness, pain, and weakness in the hands and feet
- Anemia with red blood cells that are smaller than normal ones
- Encephalopathy, memory loss, seizures, coma
Many children have no physical symptoms at the time of the exposure, but potentially permanent damage can still be occurring. Testing for lead exposure should be considered in children who grow slower than others at the same age or who have anemia, sleep problems, hearing loss, or speech, language or attention deficits.
Finding a Lead Test
How can I get a lead test?
Lead testing is usually performed at a doctor’s office or another medical setting like a hospital or lab. A doctor normally orders lead tests, but they may be available without orders at a walk-in lab.
Can I take the test at home?
Lead at-home test kits are not available, as they require a blood sample to be taken. Mobile phlebotomy services may be available in your area; they can take your sample and deliver it to a local lab for testing. But a self-administered home test is unavailable.
How much does the test cost?
The cost of a lead test will vary depending on factors such as where the test is done and whether you have health insurance. When ordered by a doctor, insurance typically covers the test, although you may have to pay a copay or deductible. Your doctor’s office, lab, and health plan can provide information about any out-of-pocket costs that may be your responsibility.
Taking a Lead Test
The lead test usually requires a blood sample, which is usually taken from your arm in a doctor’s office, health clinic, hospital, or lab.
Before the test
Usually, no special preparation is required for a lead test.
During the test
A blood sample is taken from a vein in your arm. The person taking the sample may tie a band around your upper arm and will clean the area where the needle will be inserted into your skin. A small amount of blood is drawn into a tube. You may feel a slight sting when the needle enters your skin.
The process of taking a blood sample usually takes only a few minutes.
After the test
At a doctor’s office or lab, you will be asked to apply gentle pressure to the site with a bandage or a piece of gauze after the needle is withdrawn. This will help stop bleeding and may prevent bruising. Next, the site will be bandaged. You may resume your normal activities following the test.
A blood draw is a very low-risk procedure. You may have slight bruising at the site where the blood sample was taken.
Lead Test Results
Receiving test results
The doctor who ordered your lead test may share the results with you, or you may be able to access them through an online patient portal. Lead results are usually available within a few business days.
Interpreting test results
The higher the test result, the more lead there is in the blood. However, the amount of lead in the blood does not necessarily reflect the total amount in the body. This is because most lead (80% to 90%) is stored in bones and teeth. The danger that a particular lead level represents depends on your age and health, the amount of lead you are exposed to, and the amount of time you are exposed to elevated lead levels.
Exposure to lead is not healthy for anyone, but children are more vulnerable to its effects. The CDC uses a blood lead reference value or BLL of 5 micrograms per deciliter (5 mcg/dL) to identify children with lead levels much higher than most children.
Children with elevated BLLs should be evaluated to determine the source of lead exposure and have follow-up testing to monitor the condition. BLLs will need to be monitored until the environmental investigations and subsequent responses are complete.
If their BLLs are greater than 45 mcg/dL, the child needs chelation treatment (chelation), an oral medication that binds lead and eliminates it through the urine. Some children may not be able to take this medication and will require treatment with calcium disodium ethylenediaminetetraacetic acid (EDTA) via injection.
Children with a BLL greater than 70 mcg/dL will typically require hospitalization and immediate intervention.
In 2015, the National Institute of Occupational Safety and Health (NIOSH) designated 5 mcg/dL or above as an elevated BLL in adults. The U.S. Department of Health and Human Services recommends that BLL among all adults be reduced to less than 10 mcg/dL.
Because lead will pass through the blood to an unborn child, pregnant women need to limit their exposure to lead to maintain a low blood level and as close to zero as possible to protect the developing fetus.
Any lead level greater than 70 mcg/dL should be considered a medical emergency.
You may want to ask your doctor the following questions:
- What products in the U.S. still contain lead?
- How does lead enter the body? What should I avoid?
- Are there ways to protect me and my family if I have a job where I may be exposed to lead?