Serum lead

Alternative names:

lead - serum

How the test is performed:

Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to distend (fill 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 tourniquet 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 practice or demonstrate on a doll. The more familiar your child is with what will happen to them, and the purpose for the procedure, the less anxiety they will feel.

How the test will feel:

When the needle is inserted to draw blood, some people feel moderate pain, while others feel 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).

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