Provided herein is an all-in-one saliva collection apparatus that collects saliva to allow for the filtration of saliva in order to separate saliva components, such as extracellular proteins and nucleic acids that are not present in intact cells, from the intact cells and debris remaining in the extracted sample. The filtered saliva samples can be aliquoted into two fractions for protein and/or nucleic acid analysis. The present invention further describes long term storage at ambient temperatures of filtered salivary nucleic acids, and long term storage at ambient temperatures of filtered salivary proteins added to an ethanol solution. The filtered cell-free saliva samples have diagnostic usefulness.
