PRL: Physicians Reference Laboratory

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CLA: BLOOD LEAD

BLOOD LEAD

Certain metals (also called “heavy metals”) such as copper, selenium, magnesium, and zinc, in minute amounts, are essential for normal functioning of the cells that make up human tissue. In excess amount, they can also be toxic. Other heavy metals such as lead, mercury, and cadmium are toxic to our bodies in any amount. In this time in which we live, because of its presence in a vast number of forms and chemicals to which we are exposed, lead is one of the major toxic materials about which we must be concerned in protecting ourselves and our children. Because of public health efforts, education and new laws, the potential sources of exposure to lead have been greatly reduced, especially for those of us who do not work in industries such as those that make batteries, ceramics, and fluorescent lights. The risks are still there, but industries are taking steps to protect their workers. Gasoline still available in some areas and used in older autos may contain lead in a chemical form (the gasoline was called “Ethyl”, because of the chemical tetraethyl lead that it contained). This form of lead can be ingested through the lungs, skin, and, over the years, has been a major source of contamination of the soil. Lead is still present in the plumbing of many homes and may be ingested in the water through the gastrointestinal (GI) tract. Poorly glazed ceramics are also a potential source of lead. Contrary to paints used in our homes in and before the 1980s, most paints in homes built since then do not contain lead. However, many homes still have lead-based paint on some surfaces- surfaces on which small children can chew and, each year, children with lead toxicity continue to be identified.

A single exposure to lead, unless in an industrial setting, does not usually cause toxic symptoms. In fact, the common symptoms of long-term (“chronic”) ingestion of lead, crampy abdominal pain, constipation, headache and general irritability, are so non-specific that the diagnosis is often initially missed. In children, symptoms of chronic lead intoxication are abdominal pain, headaches, vomiting, confusion, irritability/violent tantrums, hearing deficit, muscle weakness, seizures, hair loss, neurological symptoms, and unexplained anemia. Chronic lead exposure can induce loss of intelligence or mental retardation and developmental delay. Neither Kansas, nor Missouri require that children have a blood test to check for lead exposure, though the Medicaid program requires this testing for children 6months to 5 years of age. Children will continue to be exposed to lead and we must continue to be vigilant for them and for ourselves.

As mentioned above, lead is absorbed into the body through the lungs, skin, and GI tract. When it reaches the blood, the great majority of the lead is absorbed into the red blood cells (RBCs) where it binds to hemoglobin and other chemicals. From the blood, it is dispersed through the tissues, but most of the lead is eventually stored in skeletal bone.

TESTING

As mentioned, most of the lead in the blood is found in the RBCs. Consequently, the lab requires a sample of whole blood.

TREATMENT

Fortunately, there are several good drugs available to remove lead from the blood (this is called “chelation therapy”) and, indirectly, from the tissues. If a child has swallowed a significant amount of lead, (for example, as in a fishing weight or other lead object), additional efforts will be necessary to remove the source of lead before intoxication ensues.

YOUR TEST RESULTS

If your or your child’s blood test results indicate that any lead is present, you should discuss this finding with a physician of choice or call your local health department.

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