Phenol/guanidine-based QIAzol Lysis Reagent can be used to lyse all classes of tissues but is optimized for lysis of fatty tissues, such as brain and adipose tissues. The combination of organic extraction and chaotropic disruption contributes to efficient lysis and higher yields of total RNA. The organic extraction step removes both proteins and DNA, improving the efficiency of further purification steps, for example, precipitation or spin columns. QIAGEN provides several solutions for efficient RNA purification, which integrate QIAzol lysis and RNeasy silica membrane purification technologies in single, streamlined protocols (e.g., RNeasy Plus Universal Kits for any type of tissue).