Used in neuroscience and sleep disorder research to quantify levels of orexin A in biological samples such as cerebrospinal fluid or plasma. Helps investigate conditions like narcolepsy, where orexin deficiency is a key factor. Enables researchers to study the role of orexin in regulating sleep-wake cycles, appetite, and energy homeostasis. Commonly applied in clinical studies and drug development targeting the orexin system for treatments of insomnia or excessive daytime sleepiness. Provides a reliable, sensitive method for measuring orexin A concentration in human samples, supporting both diagnostic and mechanistic studies.