Scientists say a simple blood test could predict who survives a heart attack

A routine blood test could identify which heart-attack patients have the highest risk of dying within one month of their cardiac event, according to new research.

The study, published in Nature Cardiovascular Research, focused on neutrophils, the most-common type of white blood cell in the body. These cells are part of the immune system’s front-line defense and help respond to injury and infection. Researchers found that, during severe heart attacks, the bone marrow releases not only mature neutrophils into the bloodstream, but also immature versions of the cells—a possible sign of the body’s emergency response.

A research team at the University of Münster in Germany, led by Professor Oliver Soehnlein, analyzed blood samples from more than 200 patients who had experienced a heart attack, stroke or heart failure, as well as healthy volunteers. Using advanced laboratory techniques, they identified different stages of neutrophil development and examined how the presence of immature cells was linked to the severity of their condition.

The team discovered that the release of immature neutrophils was most pronounced in patients with ST-elevation myocardial infarction (STEMI), the most severe form of heart attack, which occurs when a coronary artery becomes completely blocked.

In some cases, researchers detected extremely immature precursor cells known as preneutrophils, which would normally remain inside the bone marrow. These cells were identified through a measurement known as immature granulocytes, which can be detected using a standard blood count.

The findings suggest that the more immature immune cells present in a patient’s bloodstream, the more severe their condition, with Soehnlein telling Newsweek that there is “a clear relationship” between clinical severity and prevalence of immature granulocytes in the bloodstream. Importantly, the study found that patients with the highest levels of these immature cells faced a significantly greater risk of dying within 30 days of their heart attack.

Soehnlein, a professor of Regulatory Mechanisms of Inflammation and director of the Institute of Experimental Pathology, said: “Immature granulocytes appear to predict outcome better than any other single parameter, and this is immediately available at low cost so can easily be implemented in clinical routine.

“Biologically, it makes sense that immature granulocytes are a strong predictor of outcome. Our plasma proteomics data indicate that these cells closely correlate with the inflammatory burden in patients after a heart attack, hence we consider immature granulocytes as biosensor of overt inflammation,” he continued.

To test the reliability of the findings, the team validated the results in two additional patient groups containing several hundred people. According to the researchers, immature granulocytes levels outperformed established biomarkers in predicting short-term mortality risk. Even after accounting for other known risk factors, the association remained strong. The findings could eventually help physicians identify high-risk patients as soon as they arrive at the hospital, allowing closer monitoring and potentially more targeted treatment.

However, Soehnlein notes that additional studies are needed before immature granulocytes measurements can be adopted as part of routine clinical practice. No correlation was found between age and immature granulocytes, but sex differences in risk prediction were found in one cohort.

“Immature granulocytes were predictive of outcome even in patients with a variety of comorbidities including diabetes, hypertension, atrial fibrillation or a history of a cardiac event,” Soehnlein told Newsweek. “This finding underscores the broad applicability of immature granulocytes as predictors of outcome in a cardiovascular risk cohort. This may help to stratify patients and to provide optimal care to those with high counts of immature granulocytes.”

Looking ahead, the team hopes to better understand the biological signals that trigger the release of immature immune cells during a heart attack. While Soehnlein acknowledges that it is difficult to generate causality in a patient-led study, he believes it is likely that “overt inflammatory responses are key drivers to neutrophil mobilization” and could in turn lead to breakthroughs in therapeutic interference strategies.

Reference

Richter, M., von Göwels, J., Fähndrich, M., et al. (2026). Depth of neutrophil mobilization stratifies survival in ST-elevation myocardial infarction. Nature Cardiovascular Research. https://doi.org/10.1038/s44161-026-00836-0

Contact Newsweek editors on this story: Kara Dolman and James Debens