Diagnostic Challenges Associated with Rhythmic, Pulsatile Hormones in Humans

Pulsatile hormones are essential for regulating growth, metabolism, and reproduction in humans. These hormones are released in bursts, with levels fluctuating based on circadian rhythms and physiological demands. For example, growth hormone (GH) is secreted during sleep to promote tissue repair, while luteinizing hormone (LH) pulses drive ovulation and fertility. This review shows recent advances in understanding pulsatile hormones and their circadian rhythms, and for the first time, systematically outlines the diagnostic challenges posed by their pulsatile nature. We also propose mitigation strategies for pre-analytical variability and suggest alternative tests to improve diagnostic accuracy. Key words: Pulsatile hormones; circadian rhythms; follicle-stimulating hormone; luteinizing hormone; prolactin; growth hormone; thyroid-stimulating hormone; insulin; adrenocorticotropic hormone; cortisol