ESR

ESR is an acronym that can refer to several different concepts across medicine, science, and professional organizations. The meaning depends on the context in which it is used.

Erythrocyte sedimentation rate (ESR) is a non-specific blood test that measures the rate at which red blood cells settle in a period of one hour. It is used to detect inflammation and monitor disease activity, though it does not identify the cause. Results are influenced by factors such as age, sex, anemia, pregnancy, and medications, and reference ranges vary by laboratory.

Equivalent Series Resistance (ESR) refers to the internal resistance within an electrical capacitor. ESR causes energy dissipation and can affect ripple current, startup behavior, and frequency response, especially at high frequencies. ESR depends on capacitor type and construction, temperature, aging, and operating frequency, and is a key parameter when selecting capacitors for power electronics.

Electron spin resonance (ESR), also known as electron paramagnetic resonance (EPR), is a spectroscopy technique for studying materials and molecules that contain unpaired electrons. By applying microwave radiation in a magnetic field, ESR detects transitions between electron spin states. It is widely used in chemistry, biology, and materials science to characterize free radicals, transition metal ions, and defects in solids.

European Society of Radiology (ESR) is a professional association for radiologists in Europe. The society supports education, research, and the development of guidelines and standards. It organizes the annual European Congress of Radiology and publishes journals and educational materials, serving member societies across the continent.