What It Is

A lead test is used to determine the amount of lead in the blood.

Why It's Done

Lead is a heavy metal found naturally in the environment as well as in many common consumer products. Though it serves no purpose in the human body, most people have a small amount of it in their bodies because it's so prevalent in our surroundings.

In adults, a low level of lead exposure isn't considered dangerous. However, in babies and young kids whose brains are still developing, even a small amount of lead can cause learning disabilities and behavioral problems. At higher levels, lead exposure can cause seizures, coma, and even death.

Doctors determine whether to do a blood lead test and when based on a child's risk for lead poisoning. Those who are considered at risk — such as kids who live in cities or in houses built before 1978 (the year that regulations began requiring that lead-containing paints could not be used in households) or who are exposed to lead through a parent's occupation — are usually tested at ages 1 and 2 years, and might require additional testing until age 6.

Preparation

No special preparations are needed for this test. Having your child wear a short-sleeve shirt on the day of the test can make things faster and easier for the technician who will be drawing blood.

The Procedure

A health professional will usually draw the blood from a vein. For an infant, the blood may be obtained by puncturing the heel with a small needle (lancet). If the blood is being drawn from a vein, the skin surface is cleaned with antiseptic, and an elastic band (tourniquet) is placed around the upper arm to apply pressure and cause the veins to swell with blood. A needle is inserted into a vein (usually in the arm inside of the elbow or on the back of the hand) and blood is withdrawn and collected in a vial or syringe.

After the procedure, the elastic band is removed. Once the blood has been collected, the needle is removed and the area is covered with cotton or a bandage to stop the bleeding. Collecting blood for this test will only take a few minutes.

What to Expect

Either method (heel sticking or vein withdrawal) of collecting a sample of blood is only temporarily uncomfortable and can feel like a quick pinprick. Afterward, there may be some mild bruising, which should go away in a few days.

Getting the Results

The blood sample will be processed by a machine. The results of routine blood lead screening tests are usually reported within a few days.

If lead levels in the blood are found to be slightly elevated, your doctor may give you information on reducing your child's lead exposure. For higher levels, your local health department may get involved to help detect lead sources in your home.

Risks

The lead test is considered a safe procedure. However, as with many medical tests, some problems can occur with having blood drawn:

• fainting or feeling lightheaded
• hematoma (blood accumulating under the skin causing a lump or bruise)
• pain associated with multiple punctures to locate a vein

Helping Your Child

Having a blood test is relatively painless. Still, many children are afraid of needles. Explaining the test in terms your child can understand might help ease some of the fear.

Allow your child to ask the technician any questions he or she might have. Tell your child to try to relax and stay still during the procedure, as tensing muscles and moving can make it harder and more painful to draw blood. It also may help if your child looks away when the needle is being inserted into the skin.

If You Have Questions

If you have questions about the lead test, contact your doctor. Your local health department may also have information about lead exposure and testing.

Reviewed by: Steven Dowshen, MD
Date reviewed: March 2011