What is the definition of a "rare event" in flow cytometry?

In flow cytometry, a "rare event" is typically defined as an occurrence at a very low frequency within a sample, often quantified as a frequency of 0.01% or below. This definition emphasizes the challenges associated with detecting such events amidst a large background of more abundant populations. Detecting rare events is crucial in many applications, such as identifying specific cell types in immunology or cancer research, where these low-frequency populations may have significant biological relevance.

This choice underscores the technical aspect of flow cytometry, where distinguishing these small populations requires sensitive instrumentation and careful experimental design to ensure accurate detection and quantification. The ability to recognize and analyze rare events is a critical skill for professionals working with flow cytometry, as it can provide insights into disease states, immune responses, or other physiological conditions.