Blood lead level

Blood lead level (BLL), also known as blood lead concentration or lead in blood, is a measure of the amount of lead present in the blood at the time the sample is taken. Lead is a toxic heavy metal that can cause a variety of adverse health effects, particularly in children. BLL is most commonly measured in micrograms of lead per deciliter of blood (µg/dL).

Overview

Lead can enter the human body through inhalation, ingestion, or, less commonly, through the skin. Once in the bloodstream, lead is distributed to the brain, liver, kidney, and bones. It is stored in the teeth and bones, where it accumulates over time. Lead can be released back into the bloodstream, particularly during periods of stress or when bone is being broken down, such as during pregnancy or illness.

Health Effects

Elevated BLLs in children can lead to developmental delays, learning difficulties, irritability, weight loss, and hearing loss. In severe cases, it can cause seizures, coma, and even death. Adults with high BLLs may experience high blood pressure, joint and muscle pain, difficulties with memory or concentration, and mood disorders.

Sources of Lead Exposure

Common sources of lead exposure include lead-based paint (in buildings built before 1978), contaminated dust, drinking water (from lead pipes), imported canned goods, and certain hobbies (such as working with stained glass).

Screening and Diagnosis

The Centers for Disease Control and Prevention (CDC) recommends that children be tested for lead exposure at ages 1 and 2 years, or up to age 6 if not previously tested. Adults are typically tested if they have been exposed to lead through work or hobbies, or if they have symptoms of lead poisoning. BLL is measured through a blood test.

Treatment

Treatment for elevated BLLs includes removing the source of lead exposure, chelation therapy (for very high levels), and supportive care. Chelation therapy involves taking medication that binds with lead so that it can be excreted from the body.

Prevention

Preventing lead exposure is key to reducing BLLs. This includes maintaining homes built before 1978 to prevent lead paint deterioration, ensuring drinking water is lead-free, and avoiding the use of lead-containing products.

Regulations and Guidelines

In the United States, the Occupational Safety and Health Administration (OSHA) has set the permissible exposure limit (PEL) for lead in the workplace. The Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA) also regulate lead in the environment and in consumer products.

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