New blood test using circular RNA predicts imminent Alzheimer symptoms

Scientists funded by the U.S. National Institutes of Health and based at Washington University School of Medicine in St. Louis have identified a set of circular RNA (circRNA) molecules in blood that can forecast the onset of Alzheimer's disease symptoms. In a study of more than 1,200 participants, elevated levels of 34 specific circRNAs were found to triple the risk of developing symptoms and to diverge from normal levels about two to four years before clinical signs appear. The circRNA‑based model outperformed the existing blood biomarker pTau217 in long‑term prediction, offering a more dynamic indicator of brain activity.

Researchers say the test could help select patients who are on the brink of symptom onset for clinical trials and enable more precise monitoring of treatments aimed at preventing cognitive decline. Although still in the research phase and not yet ready for routine clinical use, the approach promises a less invasive and potentially cheaper alternative to current diagnostic methods that rely on imaging or spinal fluid analysis. With over 55 million people worldwide currently affected by Alzheimer’s, early detection tools such as this could have significant implications for future therapeutic strategies.