How the Test is Performed

A blood sample is needed. For information on how this is done, see: Venipuncture

How to Prepare for the Test

No special preparation is needed.

If your child is to have this test performed, it may be helpful to explain how the test will feel, and even demonstrate on a doll. Explain the reason for the test. Knowing the "how and why" may reduce the anxiety your child feels.

How the Test Will Feel

When the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the Test is Performed

This test is used to screen people at risk for lead poisoning, including industrial workers and children who live in urban areas. It is also used to see if treatment for lead poisoning is working.

While lead serves no function in our bodies, it is usually found in the body in some amount since it is so common in the environment. Low levels in adults are not thought to be harmful, but in infants and children, low levels of lead can lead to toxicity that may cause deficits in intellectual or cognitive development.

See: Lead poisoning

Normal Results

Adults:

• Less than 20 micrograms/dL of lead in the blood

Children:

• Less than 10 micrograms/dL of lead in the blood

Note: dL = deciliter

Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

What Abnormal Results Mean

Adults who have been exposed to lead should have blood lead levels below 40 micrograms/dL. Treatment is recommended if you have symptoms of lead poisoning, or if your blood lead level is greater than 60 micrograms/dL.

In children, a blood lead level greater than 10 micrograms/dL requires further testing and monitoring. The source of lead must be found and removed. A lead level greater than 45 micrograms/dL in a child's blood usually indicates the need for treatment. However, treatment may be considered with a level as low as 20 micrograms/dL.

Risks

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Alternative Names

Blood lead levels

References

McGuigan MA. Chronic poisoning: trace metals and others. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 20.

Shannon MW. Lead. In: Shannon MW, Borron SW, Burns MJ, eds. Haddad and Winchester’s Clinical Management of Poisoning and Drug Overdose. 4th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 73.

Update Date: 5/30/2012

Reviewed by: David C. Dugdale, III, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.