CAC Score Calculator

A coronary artery calcium score (CAC score) measures the amount of calcium in the walls of your heart arteries. A CT scan detects calcium deposits associated with atherosclerotic plaque. The score ranges from 0 to 400 or higher. Each imaging software calculates the score by measuring the area and density of calcium deposits. A higher score means more calcium and more plaque buildup. The CAC score is also called the Agatston score, named after the researcher who developed the scoring system. Your score directly correlates with heart attack risk over the next 10 years.

A CAC score of 100-399 falls in the moderate risk category. It indicates moderate plaque buildup that requires action but is not immediately dangerous. A score of 100 means you have atherosclerosis present, and your 10-year heart attack risk is typically 5-10%. Most doctors recommend discussing medication options like statins. Lifestyle changes including exercise, diet, stress management, and smoking cessation are essential. A score of 100 is not dangerous today, but it signals increased risk over the next decade without treatment. Many people live for years with scores in this range by following treatment recommendations.

A CAC score of zero means no detectable calcium in your heart arteries. This indicates you do not have atherosclerotic plaque and have very low heart attack risk in the next 5-10 years. A zero score is excellent and suggests your arteries are clean. However, zero score does not guarantee permanent protection. You can still develop plaque over time if you do not maintain healthy habits. Continue exercise, healthy diet, stress management, and not smoking. Get repeat scans every 5-10 years to ensure your score stays zero. A zero score at age 50 is very reassuring but not permission to ignore heart health.

A CAC score is calculated from a low-dose CT scan (also called calcium scoring CT) that shows the heart and coronary arteries. The scan takes 10-15 seconds and requires no contrast injection. Special software detects calcium deposits and measures their area and density. The Agatston method, the most common scoring system, assigns points based on the area and peak intensity of each calcified lesion. Points from all lesions are summed to calculate the total CAC score. Different software systems may give slightly different scores from the same scan. This is why follow-up scans should use the same imaging center and protocol for accurate comparison.

A CAC score of 400 or higher is considered high risk. Scores 1-99 are mild, 100-399 are moderate, and 400+ are high. A high CAC score indicates significant plaque buildup and a 10-year heart attack risk of 15% or higher. Most doctors recommend aggressive treatment including statin medication, aspirin, blood pressure control, and major lifestyle changes. High CAC scores often warrant further testing like stress tests or coronary angiography to assess the degree of artery narrowing. High scores require close follow-up and may require referral to a cardiologist for advanced treatment options.

CAC screening is recommended for asymptomatic adults age 40-75 with risk factors like high blood pressure, high cholesterol, diabetes, smoking, or family history of early heart disease. If you have no risk factors and are low risk, a CAC scan is not routinely recommended. If you have risk factors but feel fine, a CAC scan can reveal plaque you would not otherwise know about. The scan results guide treatment decisions. Many doctors order CAC scans specifically to clarify risk in people who are uncertain about starting medication. If you feel fine and have no risk factors, ask your doctor whether a CAC scan is appropriate for you.

Repeat CAC scans are typically recommended every 5 years if your score is low to moderate and stable. If your score is high or shows progression on repeat scans, your doctor may recommend more frequent monitoring every 2-3 years. If your score is zero, repeat scans every 10 years are reasonable. More frequent scans (yearly) are not recommended because calcium changes slowly and annual scanning increases radiation without changing management. The purpose of repeat scanning is to confirm that your treatment plan is working and that plaque progression is slowing or stopping.

Your percentile ranking compares your CAC score to other people of the same age and gender. If you are at the 75th percentile, your score is higher than 75% of people your age and gender. Higher percentile means more plaque relative to your peer group. Percentile ranking helps your doctor understand your risk relative to population average. A score of 100 at the 50th percentile means you are average for your age. A score of 100 at the 90th percentile means you have more calcium than most people your age, which suggests higher than average risk.

CAC scores typically do not decrease after plaque has calcified. Once calcium deposits form in your arteries, they are usually permanent. However, treatment can slow or stop the rate of calcium progression. The goal of treatment is to prevent new calcium from forming and prevent existing plaque from growing. Your follow-up CAC scan might show the same score or a slightly higher score even with good treatment. Stable scores indicate treatment is working. Rapidly rising scores despite medication suggest you need more aggressive treatment or different medications.

CAC score and cholesterol are related but separate measures. Cholesterol levels measure the amount of cholesterol in your blood. CAC score measures the result of cholesterol damage in your arteries. You can have normal cholesterol and high CAC score if you had untreated high cholesterol in the past. You can have high cholesterol today and zero CAC score if you just recently developed elevated cholesterol. The relationship is more complex than simple correlation. This is why doctors use both measures. Normal cholesterol does not guarantee clean arteries, and high cholesterol does not guarantee calcium buildup.

If your CAC score is 100 or higher, indicating plaque buildup, your doctor may recommend aspirin therapy. Low-dose aspirin (typically 81 mg daily) reduces heart attack risk by about 15-25% in people with known plaque. However, aspirin also increases bleeding risk. The decision to start aspirin depends on your age, other risk factors, and bleeding risk. Do not start aspirin without discussing with your doctor. Your doctor will weigh the heart attack risk reduction against bleeding risk to decide if aspirin is right for you. Some people benefit from aspirin, while others have more risk than benefit.

If you have a high CAC score, the most important lifestyle changes are exercise, heart-healthy diet, stress management, and not smoking. Exercise reduces cardiovascular risk by 30-40% independent of weight loss. A heart-healthy diet low in saturated fat and high in vegetables and whole grains slows plaque progression. Quitting smoking drops your heart attack risk by 50% within one year. Stress management through meditation, yoga, or therapy reduces inflammation and heart attack risk. Weight loss if overweight improves all risk factors. These changes work synergistically with medication to slow plaque progression.

CAC score results are not part of your medical records that insurers typically access unless you volunteer the information. You are not required to disclose CAC score to insurers unless applying for life or disability insurance where you sign release forms. For life insurance, a high CAC score might affect your premiums or insurability. Most health insurance plans cover CAC scans for people with risk factors. Employment is not directly affected by CAC score, though severe heart disease would affect your ability to work in physically demanding jobs.

Yes, young people can have high CAC scores if they have multiple risk factors including high cholesterol, high blood pressure, diabetes, smoking, obesity, or family history of early heart disease. Calcium starts accumulating in people's 30s and 40s if risk factors are present. A young person with high CAC requires aggressive treatment similar to older people with similar scores. Young age with high CAC actually indicates worse disease prognosis than older age with similar CAC because the disease has had time to progress.

CAC score measures only the calcified (hardened) portion of plaque. Many plaques have soft, non-calcified components that do not show on calcium scoring. Your true plaque burden might be larger than your CAC score suggests. This is why some people with moderate CAC scores have severe artery narrowing when tested with angiography. CAC score is a good predictor of risk but underestimates total plaque. Soft plaque is actually more dangerous because it ruptures more easily and causes heart attacks. Your CAC score shows calcified disease but misses some of the danger.