Used in biomedical research to quantify follicle-stimulating hormone (FSH) regulatory protein, follistatin, in biological samples such as serum, plasma, and cell culture supernatants. Enables studies on reproductive health, pituitary function, and ovarian or testicular disorders. Widely applied in endocrinology research, fertility studies, and investigation of muscle growth regulation due to follistatin's role in modulating activin and myostatin pathways. Provides a reliable, sensitive, and specific measurement method for monitoring disease progression or treatment effects in experimental models.