Hello,
I am currently performing RNA extraction from placental samples, all stored in RNAlater at -80°C some of which have been stored since 2020.
I did RNA extraction using Qiagen micro kit. and Bioanalyzer at the end RIN : N/A !!.. that happend to around 20 samples, and 4 sample made it with RIN: between 5 and 7.
what could be the problem
Thank you in advance for your support.