A blood separation cartridge for separating a multi-component blood sample into a cellular portion and a plasma portion, comprising: a housing having an inlet port and a flow channel defined within the housing in fluid communication with the inlet port, the flow channel having a junction point at which the flow channel splits into a first collection chamber for collection of the plasma portion, the first collection chamber including a first outlet port, and a second collection chamber for collection of the cellular portion, the second collection chamber including a second outlet port, wherein the second outlet port is spaced apart from the first outlet port; and a plurality of posts contained within the flow channel, wherein the flow channel has a spiral shape and the first collection chamber and the second collection chamber contain no posts, and the plurality of posts are positioned to filter and direct the cellular portion to an outside of the flow channel, which is the same direction in which inertial forces created by the spiral shape of the flow channel drive the cellular portion, characterized in that: the first outlet port includes a valve transitionable between a closed position and an open position for connecting the blood separation cartridge to a testing device for closed transfer of a portion of the plasma portion from the first collection chamber to the point-of-care testing device, the valve comprising a transfer channel surrounded by a bellows and furthermore comprising a septum having a first barrier wall and a second barrier wall, whereby when the first outlet port is positioned over a receiving port of the testing device and is pushed in a direction of the receiving port of the testing device, the bellows is deformed and the transfer channel opens the septum, thereby allowing the plasma portion to flow through the first outlet port and the receiving port into the testing device in a closed manner without exposure of the plasma portion during transfer from the blood separation cartridge to the testing device. a housing having an inlet port and a flow channel defined within the housing in fluid communication with the inlet port, the flow channel having a junction point at which the flow channel splits into a first collection chamber for collection of the plasma portion, the first collection chamber including a first outlet port, and a second collection chamber for collection of the cellular portion, the second collection chamber including a second outlet port, wherein the second outlet port is spaced apart from the first outlet port; and a plurality of posts contained within the flow channel, wherein the flow channel has a spiral shape and the first collection chamber and the second collection chamber contain no posts, and the plurality of posts are positioned to filter and direct the cellular portion to an outside of the flow channel, which is the same direction in which inertial forces created by the spiral shape of the flow channel drive the cellular portion, characterized in that: the first outlet port includes a valve transitionable between a closed position and an open position for connecting the blood separation cartridge to a testing device for closed transfer of a portion of the plasma portion from the first collection chamber to the point-of-care testing device, the valve comprising a transfer channel surrounded by a bellows and furthermore comprising a septum having a first barrier wall and a second barrier wall, whereby when the first outlet port is positioned over a receiving port of the testing device and is pushed in a direction of the receiving port of the testing device, the bellows is deformed and the transfer channel opens the septum, thereby allowing the plasma portion to flow through the first outlet port and the receiving port into the testing device in a closed manner without exposure of the plasma portion during transfer from the blood separation cartridge to the testing device.