The present invention generally relates to systems and methods for delivering and/or receiving a substance or substances such as blood from subjects. In one aspect, the present invention is directed to devices and methods for receiving or extracting blood from a subject, e.g., from the skin and/or from beneath the skin, using devices containing a substance transfer component (for example, one or more needles or microneedles) and a reduced pressure or vacuum chamber having an internal pressure less than atmospheric pressure prior to receiving blood. In some embodiments, the device may contain a “snap dome” or other deformable structure, which may be used, at least in part, to urge or move needles or other suitable substance transfer components into the skin of a subject. In some cases, for example, the device may contain a flexible concave member and a needle mechanically coupled to the flexible concave member.
