The amount of an ingested or injected substance that results in the death of 50 percent of the test population is:

The amount of an ingested or injected substance that results in the death of 50 percent of the test population is:

• A. LC50
• B. LD50
• C. DC50
• D. IS50

Answer: (B)

LD50 is the amount of a substance that, when taken into the body by ingestion or injection, would be expected to kill 50% of a test population. It’s expressed as a dose per body weight (for example, milligrams per kilogram), reflecting how much substance is needed relative to size to produce death in half the group. This differs from LC50, which is about the concentration of a substance in air that would kill 50% of a population via inhalation. The other options aren’t standard measures for lethal dose through ingestion or injection, so LD50 is the appropriate term here. Keep in mind LD50 is a comparative toxicology tool based on animal testing and has limitations due to species differences, testing conditions, and extrapolation to humans.

LD50 is the amount of a substance that, when taken into the body by ingestion or injection, would be expected to kill 50% of a test population. It’s expressed as a dose per body weight (for example, milligrams per kilogram), reflecting how much substance is needed relative to size to produce death in half the group. This differs from LC50, which is about the concentration of a substance in air that would kill 50% of a population via inhalation. The other options aren’t standard measures for lethal dose through ingestion or injection, so LD50 is the appropriate term here. Keep in mind LD50 is a comparative toxicology tool based on animal testing and has limitations due to species differences, testing conditions, and extrapolation to humans.