Abstract: The present invention is generally directed to systems and methods for sampling fluids from subjects. The fluid may be any suitable bodily fluid, e.g., blood or interstitial fluid. In some cases, the subject is a patient. The subject may have a device that can be applied to the skin of the subject (e.g., by the subject, or another person), and the device is able to obtain a sample of fluid. The fluid may be stored within a reservoir in the device, and the fluid may be obtained from the subject at any convenient time, e.g., at home, away from a healthcare setting, etc. In some embodiments, the device, or a portion thereof, may be returned to a clinical and/or laboratory setting to analyze the fluid stored within the device.