The invention is directed to methods and devices for efficient separation of plasma from whole blood which are suitable for point of care use in resource poor environments. In some embodiments, elements of such devices comprise (a) a sample collection receptacle (SCR) with at least one port, the sample collection receptacle capable of holding a predetermined volume of a sample of undiluted whole blood drawn through a port; (b) a filter chamber having an inlet and an outlet, and containing at least one filter capable of separating plasma from blood cells as sample passes from an inlet side to an outlet side of the at least one filter whenever the filter chamber is placed in fluid communication with a port of the sample collection receptacle; and (c) a manually driven pump operationally associated with the SCR and filter chamber for (i) drawing a predetermined volume of sample into the SCR by a first user action and (ii) driving the predetermined volume at a substantially constant linear flow under a pressure not exceeding 2 psi from the SCR through the filter chamber and the outlet of the filter chamber by a second user action.