The FSH test helps diagnose and monitor reproductive and endocrine disorders. High FSH levels in women can be associated with menopause or primary ovarian insufficiency, presenting with symptoms such as irregular periods or hot flashes. Low FSH levels might suggest pituitary or hypothalamic disorders. In men, elevated FSH levels can indicate primary testicular failure, while low levels may point to secondary causes such as pituitary dysfunction. The test is crucial for evaluating fertility issues, menstrual irregularities, and overall reproductive health.