Rapid analysis of blood samples at the point-of-care is of great interest to avoid the use of large centralised analytical infrastructures, to reduce the time to answer and to reduce the cost of the analysis. Blood is a complex matrix containing a large number of analytes dissolved in plasma and also a large number of cells. Most of the analytical protocols to detect blood analytes involve the removal of the red blood cells because they may interfere with the analytical signal. Microfludidc systems offer the potential of being a small self-conatined device where the analytical assay may be performed in an automated manner. This work is focused on the development of a microfluidic module for blood sample preparation, in particular for plasma separation. Based on a previously designed single-15 trench system, we applied the integration of polymer micropumps with multilayer laminated microfluidic cartridges for high volume of plasma separation from whole blood. We evaluated the use of a multitrench system with the objectives of increasing the efficacy of the device, reducing the assay time and increasing the percentage of extracted plasma. In the first place, an optimization of the multi-trench system yield an increase in plasma filtration efficiency. Additionally, a reduction of blood sample volume led to a satisfactory plasma extraction without the need of diluting the samples. Furthermore we evaluated the effect of the flow rate in the cell sedimentation time for an efficient extraction. Finally, different methods were tested to avoid bubble formation capable of raise red blood cells from the bottom of trench, of which the use of miscible and immiscible liquids to cover top the trenches obtained the most satisfactory results fluids.