50% Neutralization Factor

**Semantic type:** Quantitative Concept

**Definition:** The quotient of the test sample ED50 value divided by the reference sample ED50 value. ED50 is the dilution of sample containing neutralizing antibody that is able to neutralize and reduce 50% of infectivity, biological or biochemical function, or total cell cytotoxicity.

**Synonyms:** - 50% NEUTRALIZATION FACTOR - NF50