The present invention generally relates to systems and methods for delivering and/or receiving a substance or substances such as blood, from subjects, e.g., from the skin and/or from beneath the skin. In one aspect, the present invention is generally 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 fluid transporter (for example, one or more microneedles), and a storage chamber having an internal pressure less than atmospheric pressure prior to receiving blood. In some cases, the device may be self-contained, and in certain instances, the device can be applied to the skin, and activated to receive blood from the subject. The device, or a portion thereof, may then be processed to determine the blood and/or an analyte within the blood, alone or with an external apparatus. For example, blood may be received from the device, and/or the device may contain sensors or agents able to determine the blood and/or an analyte suspected of being contained in the blood. In another aspect, the present invention is generally directed to arrangements of skin insertion objects such as microneedles and methods of forming and arranging skin insertion objects. Other aspects of the present invention are directed at other devices for receiving blood (or other bodily fluids, e.g., interstitial fluid), kits involving such devices, methods of making such devices, methods of using such devices, and the like.