Understanding Heart Biomarkers: What Your Blood Can Tell About Your Heart
Symptoms such as shortness of breath, fatigue or edema are often non-specific - in other words, they may or may not be caused by heart failure. In order to rule out other diseases, doctors look for certain biomarkers in the blood. BNP, NT-proBNP and troponin are considered reliable indicators both for the diagnosis of heart failure and for therapy monitoring.
When you feel symptoms like shortness of breath, tiredness, or swelling in your legs, it can be hard to know what’s causing them. These symptoms might be due to heart failure—but they could also be caused by other conditions. That’s where blood tests for heart biomarkers come in.
What are biomarkers?
Biomarkers are natural substances your body makes. When your heart is under stress or not working properly, it releases more of certain biomarkers into your blood. Doctors can measure these to help figure out what’s going on.
The most important heart-related biomarkers are:
- BNP (B-type Natriuretic Peptide)
- NT-proBNP (N-terminal pro B-type Natriuretic Peptide)
- Troponin
BNP and NT-proBNP
These are hormones made by your heart when it’s working harder than normal—like when it’s struggling to pump blood. They help your body get rid of extra salt and water, which lowers blood pressure and eases the heart’s workload. High levels of BNP or NT-proBNP in your blood can be a sign of heart failure.
Brain natriuretic peptide (BNP) levels increase markedly in left ventricular dysfunction and the level in heart failure correlates with symptom severity. BNP can therefore be an important clinical marker for the diagnosis of heart failure in patients with unexplained dyspnoea.
Brain natriuretic peptide (BNP) levels increase markedly in left ventricular dysfunction and the level in heart failure correlates with symptom severity. BNP can therefore be an important clinical marker for the diagnosis of heart failure in patients with unexplained dyspnoea.
Other clinical applications, such as screening for asymptomatic ventricular dysfunction, establishing the prognosis or guiding the titration of drug therapy and prediction of future cardiovascular events, are under investigation but have not yet been sufficiently validated for widespread clinical use.
In the UK, BNP and NT-proBNP blood tests are used to help diagnose heart failure, especially in cases of sudden or severe symptoms. A normal BNP result can help rule out heart failure, while elevated levels warrant further investigation with an ECG and specialist assessment. Specifically, NICE guidelines recommend that individuals with suspected heart failure and an NT-proBNP level above 2000 ng/L (236 pmol/L) should be urgently referred for specialist assessment and echocardiography within two weeks. These tests are powerful tools that help doctors understand how your heart is doing. If you’re experiencing symptoms like breathlessness or swelling, talk to your doctor—they may recommend checking your heart biomarkers to get a clearer picture of your health.
Troponin
Troponin is a special protein found in your heart muscle. It helps your heart contract and pump blood. There are two types that are only found in the heart:
- Troponin I (cTnI)
- Troponin T (cTnT)
These proteins usually stay inside your heart cells. But if your heart is damaged—like during a heart attack, heart failure, or heart valve disease—these proteins leak into your blood. That’s why doctors check your troponin levels when they think something might be wrong with your heart.
Levels rise within 3 hours of a heart attack, peak at 24 hours, and can stay high for up to 2 weeks. High troponin can also be caused by other conditions like kidney disease, infections, or stress. Doctors use your symptoms, history, and other tests along with troponin results to make an accurate diagnosis and guide treatment.
Good to know
As a general rule, the higher the troponin value, the greater the probability of a heart attack. High biomarker values also in other diseases The cause of conspicuously high biomarker values for troponin, BNP or NT-proBNP should always be clarified in detail, as they can also be elevated in other diseases - such as acute kidney failure, rheumatic diseases, lung or liver disease. Good to know: Heart patients should have their blood tested regularly for biomarkers. This also allows the doctor to recognise whether a therapy is working.
- References
- www.nice.org.uk/cks-uk-only
- www.bhf.org.uk/informationsupport/heart-matters-magazine/medical/ask-the-experts/troponin
- www.webmd.com/heart-disease/heart-failure/bnp-blood-test
- my.clevelandclinic.org/health/diagnostics/22629-b-type-natriuretic-peptide
- ecgwaves.com/topic/cardiac-troponin-i-tni-and-t-tnt-interpretation-and-evaluation-in-acute-coronary-syndromes/
- my.clevelandclinic.org/health/diagnostics/22770-troponin-test
- www.acc.org/latest-in-cardiology/articles/2016/02/26/09/34/using-cardiac-troponin-in-the-diagnosis-and-management-of-putatively-stable-ihd
- www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Acute-and-Chronic-Heart-Failure
9-UK-5-16529-01 08-2025