Biobanks store vast amounts of frozen blood samples, offering an invaluable resource for medical research. However, one major hurdle has been extracting high-quality RNA from these samples—especially when stored for long periods without RNA-preserving chemicals. Researchers at Umeå University have developed a method to overcome this challenge, allowing successful RNA sequencing from buffy coat samples stored at -80°C for up to 23 years.

The study tested RNA extraction from frozen blood samples collected in the Northern Sweden Health and Disease Study (NSHDS). Using a CryoXtract CXT 350 system, the researchers carefully removed frozen cores and immersed them in an RNA preservative before extraction. This approach, combined with two different RNA library preparation methods, yielded high-quality RNA suitable for sequencing. Impressively, over 92% of the samples had RNA Integrity Numbers (RIN) of 6 or higher, indicating they were viable for further analysis.

Flowchart depicting the origin of all sequenced samples

This breakthrough opens new possibilities for transcriptomic research using existing biobank samples. By unlocking RNA sequencing from long-stored frozen blood, researchers can now analyze gene expression in large-scale population studies, potentially leading to new insights into diseases like cancer.