Classically,<unk> " or "lead intoxication" has been defined as exposure to high levels of<unk>  typically associated with severe health effects. Poisoning is a pattern of symptoms that occur with toxic effects from mid to high levels of exposure; toxicity is a wider spectrum of effects, including subclinical ones (those that do not cause symptoms). However, professionals often use<unk> " and "lead toxicity" interchangeably, and official sources do not always restrict the use of<unk> " to refer only to symptomatic effects of<unk> . The amount of<unk>  in the blood and tissues, as well as the time course of exposure, determine toxicity.<unk>  may be acute (from intense exposure of short duration) or chronic (from repeat low-level exposure over a prolonged period), but the latter is much more common. Diagnosis and treatment of<unk>  exposure are based on blood<unk>  level (the amount of<unk>  in the blood), measured in micrograms of<unk>  per deciliter of blood (μg/dL). Urine<unk>  levels may be used as well, though less commonly. In cases of chronic exposure,<unk>  often sequesters in the highest concentrations first in the bones, then in the kidneys. If a provider is performing a provocative excretion test, or "chelation challenge", a measurement obtained from urine rather than blood is likely to provide a more accurate representation of total<unk>  burden to a skilled interpreter. The US Centers for Disease Control and Prevention and the World Health Organization state that a blood<unk>  level of 10 μg/dL or above is a cause for concern; however,<unk>  may impair development and have harmful health effects even at lower levels, and there is no known safe exposure level. Authorities such as the American Academy of Pediatrics define<unk>  as blood<unk>  levels higher than 10 μg/dL.<unk>  forms a variety of compounds and exists in the environment in various forms. Features of poisoning differ depending on whether the agent is an organic compound (one that contains carbon), or an inorganic one. Organic<unk>  is now very rare, because countries across the world have phased out the use of organic<unk>  compounds as gasoline additives, but such compounds are still used in industrial settings. Organic<unk>  compounds, which cross the skin and respiratory tract easily, affect the central nervous system predominantly.
Lead poisoning
Anxiety disorder
Mercury poisoning
Iron-deficiency anemia
Zinc toxicity
Malabsorption
Iron poisoning
Polyneuropathy