The steps for preparing the lysate are different depending on the starting material. Please ensure you follow the correct procedure for your starting material (see the section Disrupting and Homogenizing Starting Materials and the different lysate preparation protocols here). The subsequent steps detailed in Genomic DNA removal and total RNA purification are the same in all cases. This protocol is designed for the isolation of all sizes of RNA (including miRNA) from a wide variety of biofluids derived from all human and animal sources collected with nasal or throat swabs. Follow this protocol for isolating RNA from viruses collected with nasal or throat swabs.