Forensic Toxicology and Toxicokinetics

The application of toxicological science to legal investigations involving drugs, alcohol, poisons, and other potentially harmful substances.

The study of how a substance is absorbed, distributed, metabolized, and eliminated by the body.

The study of how a toxic substance interacts with biological targets and produces effects in the body.

Absorption, distribution, metabolism, and excretion.

The fraction of an administered dose that reaches systemic circulation unchanged.

Metabolism occurring principally in the intestinal wall or liver before an orally administered substance reaches systemic circulation.

A theoretical volume relating the amount of a substance in the body to its measured plasma concentration.

The time required for the amount or concentration of a substance to decrease by half under specified kinetic conditions.

Elimination in which the rate of removal is proportional to the substance's concentration or amount.

Elimination in which a relatively constant amount of a substance is removed per unit time over the relevant concentration range.

The relationship between the amount of exposure to a substance and the magnitude or frequency of a biological effect.

Exposure occurring over a relatively short period, potentially producing rapid harmful effects.

Repeated or continuous exposure over an extended period that may produce cumulative or delayed effects.

The estimated dose of a substance expected to cause death in 50 percent of a defined experimental population under specified conditions.

No. Individual susceptibility, exposure route, duration, and other factors affect outcomes.

A measure comparing a dose associated with toxicity to a dose associated with the desired therapeutic effect.

A product of substance metabolism that can itself cause harmful biological effects.

The buildup of a substance in an organism when uptake exceeds elimination over time.

Tolerance is reduced response to a given dose after repeated exposure; dependence involves physiological or psychological adaptation that may produce withdrawal or compulsive use.

An interaction in which combined exposure produces a greater effect than expected from the sum of individual effects.

An interaction in which the combined effect is approximately equal to the sum of individual effects.

An interaction in which one substance reduces or opposes the effect of another.

A substance that inhibits enzymes responsible for breaking down acetylcholine, potentially causing excessive cholinergic activity.

Inhibition of acetylcholinesterase, which can lead to accumulation of acetylcholine at nerve junctions.

It binds strongly to hemoglobin and disrupts oxygen transport and utilization, producing tissue hypoxia.

Hemoglobin bound to carbon monoxide rather than oxygen.

Conventional pulse oximeters may not reliably distinguish oxyhemoglobin from carboxyhemoglobin.

Inhibition of cellular respiration, particularly through interference with mitochondrial cytochrome c oxidase.

A condition involving increased hemoglobin iron in the ferric state, reducing effective oxygen transport.

Its metabolism can produce formic acid, contributing to metabolic acidosis and visual or neurological injury.

Its metabolites can cause metabolic acidosis and kidney injury, including calcium oxalate crystal formation.

Disruption of multiple enzymes and biological processes, including heme synthesis and neurological function.

Mercury compounds can bind cellular proteins and disrupt neurological, renal, and other biological functions.

It is a toxic metalloid whose exposure may cause gastrointestinal, cardiovascular, neurological, and other systemic effects.

A group of tests intended to detect selected substances or drug classes in a specimen.

Screening panels cover limited substances and may fail to detect compounds outside their scope or below their detection limits.

The lowest amount or concentration of an analyte that can be reliably distinguished from background under specified conditions.

The lowest analyte concentration that can be measured with acceptable precision and accuracy under specified conditions.

A change in analytical response caused by other components of the biological specimen.

A reduction in the measured signal of an analyte caused by competing components during ionization.

A specified concentration used to classify a test result as positive or negative for a defined analytical or regulatory purpose.

An analytical cutoff is a testing decision threshold; an impairment-related concentration concerns possible functional effects and may vary among individuals.

The amount of ethanol in a specified quantity of blood, expressed using a defined unit such as grams per deciliter.

Approximately 0.08 gram of ethanol per 100 milliliters of blood, equivalent to 80 milligrams per deciliter.

0.12 percent.

An approximate blood alcohol concentration based on factors such as alcohol consumed, body mass, distribution assumptions, and elimination.

Absorption, distribution, metabolism, drinking history, and individual variability can produce substantial uncertainty.

The estimation of an earlier alcohol concentration from a later measurement using assumptions about alcohol kinetics.

No. A defensible estimate requires evaluation of absorption status, elimination variability, timing, and other relevant factors.

No. Interpretation requires clinical or postmortem context, tolerance, interactions, specimen characteristics, and other findings.

The initial screening reaction does not establish confirmed presence of the target drug; the discrepancy must be evaluated according to the laboratory's validated procedures.