Disclosed is a separation media, comprising an upstream layer, comprising fibers, wherein the upstream layer has a mean flow pore size of 8 microns or less; and a downstream layer, comprising fibers. The separation media is designed to separate red blood cells from liquid specimens such as blood and allow a filtrate, such as blood plasma, to flow from said downstream layer. Also provided is a diagnostic test device incorporating the separation media. Further disclosed is a method for separating red blood cells from a liquid specimen.