Used in immunological research to quantify eosinophil chemotactic factors in biological samples such as serum, plasma, and cell culture supernatants. Helps in studying allergic responses, asthma, and parasitic infections by measuring the levels of specific chemokines that attract eosinophils to inflammation sites. Enables researchers to evaluate the effectiveness of anti-inflammatory treatments and understand the mechanisms behind eosinophil activation and migration in disease models.