Apparatus for the separation of plasma

Apparatus (1) for absorbing blood (19) and separating blood components as a sample liquid (2), comprising:

• a feed device (13) for receiving the blood (2),
• a separating device for separating blood components as the sample liquid (2),
• a channel (3) which takes up the sample liquid (2) by capillary forces, and
• a fill device for filling the channel (3) with the sample liquid (2) in an inlet or feed region (18) of the channel (3),
• wherein the separating device includes a membrane (15) having first and second opposing surfaces, an annular peripheral area, and a central region surrounded by the annular peripheral region,
• wherein the first and second opposing surfaces are both flat within the annular peripheral area, and
• wherein the first and second opposing surfaces are both curved such that the membrane (15) is domed, convexly curved, and projects into the filling device starting from the annular peripheral area periphery of the membrane (15) to a single apex in a direction of filling and a spacing of the membrane (15) from a base of the channel (3) is from 1 to 100 microns such that the base of the channel (3) permits the sample liquid (2) flowing through the membrane (15) and leaving the apex of the membrane (15) to begin forming a droplet, and such that the droplet comes into fluid contact with the base of the channel (3) and capillary forces draw the droplet away from the apex and through the channel (3).