Abstract: Disclosed herein are systems, methods, and kits for collecting and storing a sample from a subject. A system can comprise a cartridge assembly for separation of the blood. The cartridge assembly can comprise a cartridge port configured to couple to a sample acquisition device that is usable to collect the blood from the subject. The cartridge assembly can comprise at least one blood separation membrane that is configured to separate plasma or serum from the blood. In some cases, the cartridge port can comprise a pathway that is configured to direct the blood to flow from the sample acquisition device, through the pathway, and towards the cartridge assembly. In some cases, a direction of flow of the blood through the at least one blood separation membrane can be different from a direction of flow of the blood through the pathway and towards the inner portion of the cartridge assembly.