Test Tubes (IMAGE) Rockefeller University Caption Blood contains tiny traces of exRNA, some of which can tell a lot about a person's health status. Credit The Rockefeller University Usage Restrictions Image may be used only to illustrate the research described in the accompanying release. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.