A method for extracting interstitial fluid from a target site of a user includes adhesively attaching a floating ring of a sampling module for extracting interstitial fluid to the user in the vicinity of a target site and then mounting the sampling module to the floating ring and attaching the sampling module to the user. Subsequently, the target site is penetrated with a penetration member of the sampling module. Pressure is then applied in another vicinity of the target site by a pressure ring of the sampling module and, thereafter, ISF extracted from the target site via a penetration member of the sampling module.