Atherosclerosis is diagnosed through a combination of physical exams, blood tests, and imaging studies that reveal how much plaque has built up inside your arteries and whether it’s restricting blood flow. The specific tests your doctor orders depend on your symptoms, risk factors, and which arteries are suspected to be affected. Some people learn about their atherosclerosis through routine screening before symptoms ever appear, while others are diagnosed after chest pain, leg cramps, or a cardiovascular event triggers a workup.
Physical Exam and Early Clues
A diagnosis often starts with a stethoscope. When plaque narrows an artery, blood flowing past the obstruction creates a whooshing sound called a bruit. Your doctor can hear this by listening to specific spots on your body: the sides of your neck (carotid arteries), your abdomen (renal and aortic arteries), or over arteries in your groin and legs. A bruit in the neck is one of the earliest detectable signs of carotid artery disease, while one heard in the belly can signal narrowing of the arteries supplying your kidneys.
Beyond listening, your doctor will check pulses at your wrists, ankles, and feet. Weak or absent pulses in the legs suggest blockages in the peripheral arteries. Other visible clues include slow-healing wounds on the feet, cool or discolored skin on the lower limbs, and in some cases, yellowish fatty deposits around the eyelids or over tendons, which can point to chronically high cholesterol.
Blood Tests That Flag Risk
Blood work doesn’t directly show plaque inside your arteries, but it reveals the conditions that drive plaque formation and helps determine how aggressively to investigate further.
A standard lipid panel measures your LDL cholesterol, the type most responsible for plaque buildup. Ideally, LDL stays below 100 mg/dL. For people at the highest risk of heart attacks, the target drops to below 70 mg/dL. Levels above 130 mg/dL are considered elevated for most adults.
If your cholesterol looks normal but you still have risk factors or a family history of early heart disease, your doctor may check two additional markers. High-sensitivity C-reactive protein (hs-CRP) measures inflammation in the body, and a level above 2.0 mg/L signals increased cardiovascular risk. Lipoprotein(a), a genetically determined variant of LDL cholesterol, can drive atherosclerosis even when standard cholesterol numbers look fine. It’s particularly useful to test for when heart disease runs in your family without an obvious explanation.
Coronary Artery Calcium Score
A coronary calcium scan is one of the most straightforward ways to detect atherosclerosis before it causes symptoms. It uses a quick, low-dose CT scan of your chest (no injections, no exercise) to measure calcium deposits in the walls of your heart’s arteries. Calcium accumulates in plaque over time, so the amount present reflects years of disease buildup.
Results are reported as an Agatston score, which falls into clear risk categories:
- 0: Very low risk, no detectable calcium
- 1 to 99: Mildly increased risk, some plaque present
- 100 to 299: Moderately increased risk
- 300 or higher: Moderate to severely increased risk
The raw number is only part of the picture. Your score is also compared against people of the same age, sex, and race to generate a percentile. A 48-year-old woman with a score of just 10 might land at the 93rd percentile for her demographic, meaning she has more plaque than 93% of similar women, even though her absolute score seems low. Meanwhile, a 72-year-old man with a score of 25 could fall at only the 35th percentile, where watchful waiting may be more appropriate. This percentile context is often what drives treatment decisions for people in the gray zone of cardiovascular risk.
Carotid Ultrasound
An ultrasound of the neck arteries is a painless, radiation-free way to check for atherosclerosis in the carotid arteries that supply blood to the brain. The test measures the thickness of the inner two layers of the artery wall, called the intima-media thickness. In healthy individuals, this measurement is typically under 0.8 mm. A reading at or above 1.0 mm is associated with atherosclerosis and a significantly increased risk of cardiovascular events regardless of age.
Carotid ultrasound can also directly visualize plaques, estimate how much they narrow the artery, and assess whether blood flow to the brain is compromised. It’s commonly ordered after a bruit is heard during a physical exam, after a mini-stroke, or as a screening tool in people with multiple cardiovascular risk factors.
CT Angiography
Coronary CT angiography (CTA) provides detailed images of the arteries feeding your heart. Unlike a calcium score scan, this test involves an injection of contrast dye so that the blood vessels themselves become visible. It can show not just calcified plaque but also softer, non-calcified plaque and the degree to which any blockage narrows the artery.
CTA has the highest sensitivity of any non-invasive imaging method for detecting significant coronary artery disease, catching about 97% of significant blockages. Its main limitation is specificity: it sometimes flags narrowing as severe when it’s actually more modest, particularly when heavy calcification makes images harder to interpret. Still, a normal CTA is highly reassuring and can often spare patients from more invasive testing.
Stress Testing
Stress tests evaluate how well blood flows through your heart arteries when your heart is working hard. During a standard exercise stress test, you walk on a treadmill while your heart rate, blood pressure, and electrical activity are monitored. If you can’t exercise, medication is used to simulate the effect of exertion on your heart.
A basic treadmill test can reveal problems, but when doctors need higher accuracy, they add imaging. In a nuclear stress test, a small amount of radioactive tracer is injected and a camera captures how blood distributes through your heart muscle at rest and during stress. Areas that receive less blood during exertion point to blockages upstream. Stress echocardiography uses ultrasound instead, looking for portions of the heart wall that don’t contract normally when the heart is pushed to work harder. Both approaches offer better detection of significant blockages than a treadmill test alone.
Ankle-Brachial Index for Leg Arteries
The ankle-brachial index (ABI) is the simplest test for atherosclerosis in the legs. It compares blood pressure measured at your ankle with blood pressure at your arm using a standard cuff and a handheld Doppler device. The whole process takes about 10 to 15 minutes.
A normal ratio falls between 0.9 and 1.4. A reading of 0.9 or below confirms peripheral artery disease. Most people who experience cramping or pain in their legs while walking have an ABI between 0.5 and 0.9. Below 0.5 typically means blockages exist at multiple levels, and patients in this range often have pain even at rest. Values below 0.3 suggest severely compromised circulation with risk of tissue damage. On the other end, a reading above 1.4 doesn’t mean everything is fine. It usually indicates stiff, calcified arteries (common in diabetes and chronic kidney disease) and carries its own increased cardiovascular risk.
Invasive Angiography
Coronary angiography remains the definitive test for evaluating blockages in the heart’s arteries. A thin catheter is threaded through an artery in your wrist or groin up to the heart, and contrast dye is injected directly into the coronary arteries while X-ray images are captured in real time. This gives the clearest possible view of where narrowing exists and how severe it is.
Because it’s invasive, angiography is typically reserved for situations where non-invasive tests have already identified a likely problem, or when symptoms are severe enough that treatment during the same procedure is a possibility. If significant blockages are found, a stent can often be placed immediately to open the artery. If the disease is too extensive for stenting, the results guide planning for bypass surgery. When narrowing is present but not limiting blood flow, no procedure may be needed, and the focus shifts to medications and lifestyle changes.
10-Year Risk Calculators
Before ordering any imaging, many doctors start by plugging your health data into a cardiovascular risk calculator. The most widely used version, the ASCVD Risk Estimator Plus, takes your age, sex, race, blood pressure (and whether you’re on blood pressure medication), cholesterol numbers, smoking status, and diabetes history, then estimates your percentage chance of a heart attack or stroke over the next 10 years.
This score helps determine who benefits most from further testing. Someone with a 10-year risk below 5% may need nothing beyond basic blood work and lifestyle advice. Someone in the intermediate range (5% to 20%) is often the best candidate for a coronary calcium scan, since the result can tip the decision toward or away from starting preventive medication. For people already at high risk based on the calculator, treatment typically begins regardless, and imaging focuses on gauging how advanced the disease is rather than whether it exists.