Coronary artery disease screening tests help assess the risk of narrowed or blocked arteries that supply blood to the heart. Common screening methods include blood pressure measurements, cholesterol and blood sugar tests, and cardiovascular risk assessments. For some people, a coronary calcium scan may provide additional information. Electrocardiograms, stress tests, and other heart imaging tests are generally selected according to symptoms, medical history, and individual risk.
What do coronary artery disease screening tests look for?
Coronary artery disease (CAD) develops when plaque builds up inside the coronary arteries, which carry oxygen-rich blood to the heart muscle. Plaque contains cholesterol, fats, and other substances. As it accumulates, it can narrow the arteries and restrict blood flow.
Screening aims to identify cardiovascular risk factors or signs of coronary disease before a serious complication occurs. Not every screening test directly examines the coronary arteries. Some tests estimate the likelihood of developing heart disease, while others look for calcium deposits, changes in electrical activity, or reduced blood flow.
According to the National Heart, Lung, and Blood Institute (NHLBI), healthcare professionals use a person's risk factors, medical history, and test results to assess coronary heart disease. The appropriate tests depend on whether the person has symptoms, known cardiovascular disease, or an elevated risk of future heart problems.
Which screening tests are commonly used first?
1. Cholesterol and lipid profile
A lipid profile is a blood test that measures cholesterol and triglycerides, which are fats circulating in the blood. It commonly includes total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides.
High LDL cholesterol is an important risk factor because cholesterol can contribute to plaque buildup in the arteries. HDL cholesterol and triglyceride levels also help clinicians understand a person's overall lipid profile. The results are interpreted alongside factors such as age, blood pressure, smoking history, diabetes, and family history.
A lipid profile does not show whether a coronary artery is blocked. Instead, it helps estimate cardiovascular risk and guides decisions about prevention. Some lipid tests can be performed without fasting, although a healthcare professional may recommend fasting in certain circumstances.
2. Blood glucose and diabetes screening
Blood glucose testing measures the amount of sugar in the blood. An HbA1c test estimates average blood glucose over approximately the previous three months. These tests can identify diabetes or elevated blood sugar, which are relevant to cardiovascular risk assessment.
Blood glucose and HbA1c tests do not directly detect coronary artery plaque. Their role is to identify a risk factor that may influence a person's overall risk of developing cardiovascular disease. Whether testing is appropriate, and how often it should be repeated, depends on age, medical history, and established screening recommendations.
3. Blood pressure measurement
Blood pressure measurement is a routine part of cardiovascular risk assessment. It measures the force of blood against artery walls. Persistently high blood pressure can increase the risk of cardiovascular complications, including coronary artery disease.
The measurement is quick and usually performed with an inflatable cuff around the upper arm. A single reading may not fully reflect a person's usual blood pressure, so repeated measurements or home monitoring may be recommended when results are elevated or uncertain.
4. Cardiovascular risk assessment
A cardiovascular risk assessment combines information such as age, cholesterol levels, blood pressure, smoking status, and diabetes history to estimate the likelihood of future cardiovascular events. Depending on the calculator used, the estimate may cover the next 10 years or a longer period.
The NHLBI's guidance on coronary heart disease diagnosis describes risk calculators as tools that help healthcare professionals and patients understand cardiovascular risk and discuss prevention. A risk score is an estimate, not a diagnosis, and it may not capture every factor relevant to an individual.
Which heart tests can look for signs of coronary artery disease?
Additional tests may be appropriate when a person has symptoms, a strong family history, an uncertain risk estimate, or findings that need further investigation. These tests have different purposes and are not interchangeable.
5. Coronary artery calcium scan
A coronary artery calcium (CAC) scan is a specialized computed tomography (CT) scan that uses X-rays to detect calcium deposits in the walls of the coronary arteries. The result is reported as a calcium score, which reflects the amount of detected calcified plaque.
A score of zero means that the scan detected no coronary artery calcium. It does not rule out every form of coronary artery disease because plaque may be present without detectable calcium. Higher scores generally indicate a greater burden of calcified plaque and can help refine cardiovascular risk estimates.
According to Mayo Clinic's information on coronary calcium scans, the test may be useful when a person's heart attack risk is uncertain or falls into an intermediate range. It is not automatically necessary for everyone, and its results should be interpreted alongside other health information. The scan involves a small amount of radiation and may involve an out-of-pocket cost.
6. Electrocardiogram (ECG or EKG)
An electrocardiogram records the electrical signals that control the heartbeat. Small electrodes attached to the skin measure the heart's electrical activity. The test is painless and usually takes only a few minutes.
An ECG can help identify certain heart rhythm abnormalities and electrical changes that may be associated with heart muscle problems or reduced blood supply. However, it does not directly show plaque inside the coronary arteries, and a normal resting ECG does not exclude coronary artery disease.
For adults without symptoms, a resting or exercise ECG is not routinely recommended as a general screening test when cardiovascular risk is low. The US Preventive Services Task Force recommendation on ECG screening advises against this use in asymptomatic adults at low cardiovascular risk because potential harms can equal or outweigh the benefits. Testing decisions may differ when symptoms or specific clinical concerns are present.
7. Exercise stress test
An exercise stress test evaluates how the heart responds when it works harder. During the test, a person walks on a treadmill or pedals a stationary bicycle while clinicians monitor the heart rate, blood pressure, and electrical activity. If exercise is not possible, medication may be used to make the heart work harder.
Changes during exercise may suggest that the heart muscle is not receiving enough blood. Some stress tests also use ultrasound or nuclear imaging to provide additional information about heart function and blood flow.
A stress test is not a universal screening test for people who feel well. It is more commonly considered when symptoms, medical history, or other findings make further evaluation appropriate. Results must be interpreted in context because both false-positive and false-negative results can occur.
8. Coronary CT angiography
Coronary CT angiography (CCTA) uses a CT scanner and contrast dye injected into a vein to create detailed images of the coronary arteries. It can show plaque and areas where the arteries have narrowed.
Unlike a calcium scan, which detects calcium deposits, CCTA can show both calcified and noncalcified plaque. It is a diagnostic imaging test rather than a routine first-line screening test for every asymptomatic adult.
Preparation may include checking kidney function and reviewing allergies, medicines, and other health conditions. The test uses radiation and contrast dye, so the healthcare team considers potential risks before recommending it.
9. Invasive coronary angiography
Invasive coronary angiography provides detailed images of blood flow through the coronary arteries. A clinician inserts a thin tube called a catheter into a blood vessel, usually in the wrist or groin, and guides it toward the heart. Contrast dye is then injected so that X-ray images can show narrowed or blocked areas.
This procedure is generally reserved for situations in which a detailed assessment is needed, such as concerning symptoms or abnormal findings from other tests. It is not a routine screening test for people without symptoms. Because it is invasive, it carries risks, including bleeding, blood vessel injury, contrast-related complications, and, rarely, more serious complications.
The NHLBI's overview of heart tests explains how coronary angiography and noninvasive imaging help clinicians investigate suspected heart disease and plan further care.
Who should consider coronary artery disease screening?
Routine cardiovascular prevention usually begins with assessment of blood pressure, cholesterol, blood sugar when indicated, smoking status, family history, and other risk factors. Additional imaging or heart tests are considered according to the findings and the person's overall risk.
Screening and risk assessment may be particularly relevant for people with:
- High blood pressure or elevated cholesterol.
- Diabetes or a history of elevated blood glucose.
- Current or previous tobacco use.
- A family history of coronary artery disease, especially at a relatively young age.
- Other health conditions or lifestyle factors that increase cardiovascular risk.
These factors do not automatically mean that advanced cardiac testing is necessary. A clinician can determine which assessments are useful and whether the results are likely to change prevention or treatment decisions.
Does screening differ by age?
Age is an important part of cardiovascular risk assessment. For younger adults, the focus is often on identifying risk factors and building a prevention plan. As people get older, age may contribute more substantially to estimated cardiovascular risk, making regular review of blood pressure, cholesterol, and other relevant factors important.
There is no single age at which every person should receive a coronary calcium scan, stress test, or CT angiogram. The choice depends on the person's risk profile, symptoms, existing diagnoses, and whether additional testing would help guide a decision. Children and adolescents generally require a different approach based on their individual circumstances and specific risk factors.
How should you prepare for screening tests?
Preparation depends on the test. Routine blood pressure measurement usually requires no special preparation. For blood tests, ask whether fasting is necessary. For a coronary calcium scan, ECG, or stress test, follow the facility's instructions about clothing, meals, caffeine, and medicines rather than stopping prescribed treatment on your own.
Before CT angiography or invasive angiography, tell the healthcare team about kidney problems, previous reactions to contrast dye, possible pregnancy, and all medicines or supplements you take. These details can help the team determine whether any precautions or alternative tests are needed.
What happens after an abnormal screening result?
An abnormal result does not always mean that a coronary artery is significantly blocked. The next step depends on the test, the degree of abnormality, symptoms, and the person's overall cardiovascular risk. A clinician may review the result, repeat a measurement, assess other risk factors, or recommend a more specific diagnostic test.
For example, an elevated cholesterol level may lead to a discussion about cardiovascular prevention, while an unexpected finding on a heart scan may require further assessment. A calcium score, ECG, and stress test measure different things, so one result should not be interpreted as a substitute for all the others.
If you develop new or persistent chest discomfort, shortness of breath, or symptoms that occur during physical activity, seek prompt medical evaluation rather than relying on a screening test. Sudden chest pressure or discomfort, particularly with breathlessness, sweating, nausea, or pain spreading to the arm, back, neck, or jaw, may indicate a heart attack. Call your local emergency number immediately if these symptoms occur.