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Also known as: Blood Lead Test; Blood Lead Level; BLL
Formal name: Lead, blood

The Test Sample

What is being tested?

This test measures the current lead level in the blood. Lead is a soft metal present in the environment. When it is inhaled or ingested, lead can cause damage to the brain, organs, and nervous system. Even at low levels, it can cause irreversible damage without causing physical symptoms. In an infant, lead can cause permanent cognitive impairment, behavioral disorders, and developmental delays. Lead exposure can cause weakness, anemia, nausea, weight loss, fatigue, headaches, stomach pain, and kidney, nervous system, and reproductive dysfunction. Lead can be passed from mothers to their unborn children and can cause miscarriages and premature births.

In the past, lead was used in paints, gasoline, water pipes, and other household products, such as the solder used in canned food. Although these uses have been limited in the U.S., lead is still used in many products and industrial processes both in the U.S. and around the world. Housing built prior to 1978 is likely to contain lead-based paint and lead-contaminated household dust, especially if the house was built prior to 1950. Soil surrounding these houses may also be contaminated with lead.

Children under 6 years of age are the most likely to be exposed to lead because of their increased hand-to-mouth behavior and high absorption rates. The lead gets into their bodies by their ingesting lead dust or paint chips, inhaling dust, mouthing or chewing items that contain lead or have been contaminated by lead, and/or by eating contaminated food or water. Adult lead exposure is usually related to occupational or recreational (hobby) exposure. Children of those who work with lead may also become exposed when lead contamination is brought home on the work clothes of their parents.

How is the sample collected for testing?

Blood is drawn from a vein in the arm. Sometimes, blood is collected by fingerstick (or heelstick for infants). If test results from a fingerstick are abnormal, a venous blood draw should be ordered to confirm the results.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.