LD50
Abbreviation with 2 meanings
| Stands for | Lethal dose, 50% |
|---|---|
| Meanings | 2 |
| Categories | Science & Engineering, Medical |
LD50 has two meanings. It stands for Lethal dose, 50% (chemistry) or Median lethal dose (pharmacology).
Meanings of LD50 at a glance
| # | LD50 stands for | Context |
|---|---|---|
| 1 | Lethal dose, 50% | Science & Engineering › Chemistry |
| 2 | Median lethal dose | Medical › Pharmacology |
1. Lethal dose, 50%
Science & Engineering · Chemistry Abbreviations
Dose of a substance that kills half of a group of test animals, usually expressed in milligrams per kilogram of body weight. LD50 values compare acute toxicity: table salt's oral LD50 in rats is about 3,000 mg/kg, while sodium cyanide's is under 10 mg/kg.
Example: The pesticide's oral LD50 in rats is 50 mg/kg, placing it in a highly toxic category.
J. W. Trevan introduced the LD50 in 1927. A lower LD50 means a more toxic substance. LC50 is the equivalent for concentrations in air or water. Animal welfare concerns have led regulators to accept alternative test methods that use fewer animals, and the value says nothing about chronic or long-term effects.
2. Median lethal dose
Medical · Pharmacology Abbreviations
Dose of a substance that kills 50 percent of test animals under defined conditions, used historically to compare acute toxicity of drugs, chemicals and poisons. It is usually expressed in mg per kg of body weight.
Example: The pesticide's oral LD50 in rats is 5 mg/kg, placing it in the highest toxicity category.
The test was introduced by British pharmacologist J. W. Trevan in 1927. Because classical LD50 testing used many animals, regulators have largely replaced it with methods requiring far fewer animals, such as fixed-dose and up-and-down procedures. LD alone also abbreviates loading dose in clinical dosing.
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More pharmacology abbreviations
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- DLT – Dose-limiting toxicity
- ED50 – Median effective dose
- INN – International Nonproprietary Name
- MOA – Mechanism of action
- MTD – Maximum tolerated dose
- NTI – Narrow therapeutic index
- OIC – Opioid-induced constipation
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This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.