Method for separating blood plasma and metering thereof

A microfluidic device with a capillary driven plasma separation means, comprising a substantially flat porous membrane with an upper surface adapted to receive a blood sample and a lower surface, a laterally extending support structure having a hydrophilic surface, wherein the lower surface of the porous membrane and the hydrophilic surface of the support structure are configured to form an intersection in an acute angle so that a lateral capillary flow of filtered fluid is formed in a proximity of the intersection, thereby gradually filling a space between said diverging lower surface of the porous membrane and the hydrophilic surface of the laterally extending support structure, and a capillary channel configured to receive and accommodate the lateral capillary flow arriving from the space between said diverging lower surface of the porous membrane and the hydrophilic surface of the laterally extending support structure, the capillary channel comprising a channel cover and a channel bottom from the laterally extending support structure, wherein a portion of the lower surface of the porous membrane contacts the top of the channel cover, and the microfluidic device has a linear arrangement.