Abstract: A device for determining HDL cholesterol by obtaining plasma from whole blood and determining the HDL cholesterol level from the plasma. The device includes an inert substrate support or an active substrate support (e.g. one or the other layers), a physical transport medium, a microporous plasma separation membrane connected to the physical transport medium, at least one plasma collecting test membrane, a filtering membrane, LDL and VLDL reactants to form LDL and VLDL precipitates and an optional carrier precipitation membrane. The plasma collecting test membrane has reactants which will react with HDL cholesterol and indicate the HDL cholesterol level quantitatively. The filtering membrane may be located between the microporous plasma separation membrane and the transport medium or between the microporous plasma membrane and the plasma collecting test membrane and its function is to block the precipitated particles from reaching the test zone.