Lead levels - blood

Definition

Blood lead levels is a test that measures the amount of lead in the blood.

How the test is performed

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic. An elastic band is placed around the upper arm to apply pressure and cause the vein to swell with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

The blood is collected and transported in containers that do not contain lead. It is usually evaluated by atomic absorption spectroscopy.

How to prepare for the test

No dietary restriction of food or fluid is necessary.

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

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

This test is performed to screen people at risk for lead poisoning (industrial workers or children in urban areas), and to monitor the improvement of those who already have increased serum lead levels or lead toxicity.

Normal Values

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

What abnormal results mean

Adults:

• Workers exposed to lead should have blood lead levels below 40 micrograms/dL. Treatment is recommended if the level exceeds 80 micrograms/dL.

Children:

• Greater than 10 micrograms/dL of lead in the blood is abnormal. The source of lead must be identified and removed.
• Greater than 25 micrograms/dL of lead is abnormal, and may indicate the need for treatment.

What the risks are

Risks associated with having blood drawn are slight:

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

Special considerations

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.

Illustrations

Blood test

Page Content:

Blood lead levels ; blood lead level