By the time most people learn their heart is in trouble, it’s too late. The damage is done, symptoms scream for attention, and the emergency room becomes the next stop.

But new research suggests it doesn’t have to be that way.

A simple £5 blood test could quietly reveal danger before it strikes. The test measures troponin, a protein that leaks into the bloodstream when the heart is damaged. For decades, doctors have used troponin tests in hospitals to confirm heart attacks. Now, scientists are flipping the script—using the same test to predict heart problems before they happen.

A Silent Signal of a Troubled Heart

In a sweeping study published in the Journal of the American College of Cardiology, researchers analyzed data from more than 62,000 people across Europe and North America who had no history of heart disease. All participants had their troponin levels measured. Researchers also tracked other traditional risk markers—like cholesterol, blood pressure, diabetes, and smoking history— for nearly a decade.

The results were striking: people with higher troponin levels, even those within what’s typically considered a normal range, were significantly more likely to suffer a heart attack or stroke in the following 10 years.

“Troponin, even in the normal range, is a powerful indicator of silent heart muscle damage,” said Professor Anoop Shah, a cardiovascular specialist at the London School of Hygiene & Tropical Medicine and lead author of the study. “As such, the test provides an extra layer of information that we can use to boost our accuracy when predicting people’s risk.”

Right now, doctors use a formula based on conventional risk factors to estimate a person’s chances of having a cardiovascular event over the next decade. Those at low risk are left alone. Those at high risk might be prescribed statins or given lifestyle advice.

But what about everyone in the middle?

Roughly a third of adults fall into this “intermediate risk” category. Their risk is not low enough to ignore, but not high enough to treat. As a result, many go without intervention—until it’s too late.

The new study shows that adding troponin measurements to the equation can reclassify about 8% of these borderline cases into the high-risk group. “We want to identify as many high-risk people as possible,” Shah said, “so that no one misses out on the opportunity to get preventative treatment.”

A Modest Change With Big Potential

The study continues by asking what happens if we act based on this test?

Using health data from 2.1 million people in the UK, researchers modeled the impact of prescribing statins to newly reclassified high-risk individuals. For every 408 to 473 people screened with a troponin test and treated accordingly, one cardiovascular event could be prevented. In other words, this could save lives.

To be clear, the improvement in predictive accuracy was modest: adding troponin levels increased the model’s performance by a few percentage points. But in big population samples, small shifts could mean thousands of lives saved.

And crucially, the test is just £5. You could run it routinely.

Compared to MRI scans, CT angiography, or advanced genetic testing, this test can be run alongside standard cholesterol panels at a GP surgery. No specialist visit required.

A Smarter Way to Catch Risk Early?

The discovery fits into a growing movement in medicine to detect disease before symptoms show and the damage becomes irreversible.

In many ways, troponin is the heart’s quiet distress call. High-sensitivity versions of the test can pick up minute traces of the protein, long before a full-blown heart attack occurs. That’s what makes it different. It doesn’t wait for the crisis. It whispers a warning.

According to the study, both major forms of the protein—troponin T and troponin I—were predictive. For each standard deviation increase in the protein levels, the risk of cardiovascular disease rose by more than 25%.

That’s not enough to diagnose someone on its own. But in combination with traditional risk factors, it sharpens the picture dramatically.

Of course, no test is perfect. Some people with high troponin may never have a cardiovascular event. Others with low levels still might. But as Shah and colleagues argue, it’s a meaningful step toward more personalized prevention.

And in a healthcare system straining under the weight of heart disease—the leading cause of death globally—even one step forward could make a world of difference.