Low RNA concentrations can indeed be a sign of sample degradation. Several factors contribute to RNA degradation, including inadequate sample handling, prolonged storage, suboptimal storage conditions, and the presence of RNases. Here are some specific points from the references that support this: 1. **Sample Handling and Storage**: Inadequate handling and storage conditions can lead to RNA degradation. Samples should be stored properly, ideally at -80°C or frozen in liquid nitrogen to prevent degradation. 2. **RNase Contamination**: The ubiquitous presence of RNases in the environment can degrade RNA. It is crucial to use RNase-free reagents and to follow strict protocols to minimize RNase contamination during RNA extraction. 3. **Storage Duration**: The duration of storage at room temperature has a significant impact on RNA degradation. Prolonged storage can lead to substantial degradation of RNA. 4. **Extraction and Handling Issues**: Issues during the extraction process, such as incomplete homogenization, allowing the tissue to thaw before homogenization, and insufficient sample mass, can also lead to low RNA concentrations and degradation. 5. **Quality Assessment**: An A260/A280 ratio greater than 3 can indicate degradation, as it suggests the presence of degraded RNA or other contaminants. Therefore, if you are experiencing low RNA concentrations, it is likely that the sample has undergone some degree of degradation. Ensuring proper sample handling, storage, and extraction techniques can help mitigate this issue.

One more thing you can try is that add glycogen (0.5 microliters) during isopropanol storage for better precipitation of RNA. Beatriz de Arco Othman Mueen Mohammed