The apparatus of the present invention comprises an integrated membrane for separation and preservation of biomolecules. Biomolecules, such as those in blood, can be separated and preserved. The apparatus includes a housing having a matrix portion, and a fluid collection portion disposed within an inner cavity. The housing further includes an aperture permitting access to the inner cavity. The apparatus also includes a matrix disposed within the matrix portion. The matrix includes a first layer for collecting cells from the fluid, a second layer for protein adsorption, and a third layer for nucleic acid adsorption. Fluid enters the housing through the aperture, passes through the matrix, and into the fluid collection portion. Cells from the fluid in a layer of the matrix are collected; adsorbing protein from the fluid in a layer of the matrix; and adsorbing nucleic acid from the fluid in a layer of the matrix.