Agatston Score Risk Categories
The Agatston Score (Calcium Score) quantifies coronary artery calcium on non-contrast cardiac CT. It provides independent cardiovascular risk stratification beyond traditional risk factors. The following categories reflect established clinical thresholds.
| Score | Category | Plaque Burden | 10-yr MACE Risk | Key Guidance |
|---|---|---|---|---|
| 0 | No identifiable disease | None visible | <1% | Defer statin in borderline risk; reassess in 5–10 yr |
| 1–10 | Minimal plaque | Trace | ~1–3% | Lifestyle modification; statin not typically indicated |
| 11–100 | Mild plaque | Low-moderate | ~3–6% | Statin therapy favored; aggressive lifestyle change |
| 101–400 | Moderate plaque | Moderate | ~6–12% | Statin therapy strongly indicated; consider aspirin |
| >400 | Severe plaque | Extensive | >12% | High-intensity statin; aspirin; comprehensive risk reduction |
Age- and Sex-Specific Percentile Reference
A score that is "average" for age and sex still carries absolute risk. Scores above the 75th percentile for a patient's age/sex group indicate significantly elevated relative risk even when the absolute score appears low.
| Age Group | Sex | 25th %ile | 50th %ile (Median) | 75th %ile | 90th %ile |
|---|---|---|---|---|---|
| 40–44 | Male | 0 | 0 | 3 | 57 |
| 40–44 | Female | 0 | 0 | 0 | 4 |
| 45–49 | Male | 0 | 0 | 19 | 107 |
| 45–49 | Female | 0 | 0 | 0 | 13 |
| 50–54 | Male | 0 | 8 | 71 | 208 |
| 50–54 | Female | 0 | 0 | 11 | 55 |
| 55–59 | Male | 0 | 36 | 163 | 408 |
| 55–59 | Female | 0 | 0 | 40 | 121 |
| 60–64 | Male | 5 | 103 | 310 | 645 |
| 60–64 | Female | 0 | 11 | 100 | 263 |
| 65–69 | Male | 22 | 181 | 492 | 934 |
| 65–69 | Female | 0 | 40 | 185 | 413 |
| 70–74 | Male | 72 | 330 | 756 | 1287 |
| 70–74 | Female | 2 | 99 | 311 | 629 |
Reference: MESA (Multi-Ethnic Study of Atherosclerosis) percentile data. Values are approximate.
How the Agatston Score is Calculated
The score is computed from non-contrast ECG-gated cardiac CT (typically 3 mm slices, tube voltage 120 kVp). Each calcified plaque with peak attenuation >130 Hounsfield Units (HU) is identified and scored:
- 1× area (mm²) for lesions with peak 130–199 HU
- 2× area for peak 200–299 HU
- 3× area for peak 300–399 HU
- 4× area for peak ≥400 HU
The per-lesion scores are summed across all four coronary arteries (LAD, LCx, RCA, LM) to produce the total Agatston Score. This calculator accepts per-vessel scores as reported by CT reading software or a radiologist's structured report.
Clinical Utility and Statin Decision-Making
The 2018 ACC/AHA Cholesterol Guidelines incorporate coronary artery calcium (CAC) scoring as a key tiebreaker for statin initiation in patients with borderline cardiovascular risk (7.5–20% 10-year ASCVD risk). A CAC score of 0 supports deferring statins in most borderline-risk patients. A score >100 or above the 75th percentile for age/sex generally tips the decision toward initiating preventive therapy.
CAC scoring is particularly valuable in:
- Patients with borderline 10-year ASCVD risk uncertain about statin initiation
- Intermediate-risk patients with risk-enhancing factors (family history, metabolic syndrome)
- Patients reluctant to start lifelong statin therapy who want quantified data
- Younger patients (40–55) where traditional risk calculators may underestimate risk
How to Use This Calculator
Enter the Agatston score for each coronary artery vessel as reported by the CT reading software or the radiologist's structured report. Most CT reading platforms (e.g., TeraRecon, Vitrea, Syngo, 3mensio) automatically calculate per-vessel and total Agatston scores from dedicated non-contrast cardiac CT acquisitions. If you have only the total score without per-vessel breakdown, you may enter the total in any single vessel field.
The calculator sums the four vessel scores (LAD, LCx, RCA, LM) and classifies the total according to established ACC/AHA risk categories. The recommendation box reflects evidence-based guidance from the 2018 ACC/AHA Cholesterol Guidelines for borderline-risk patients.
Limitations and Considerations
CAC scoring has important limitations that must be understood in clinical practice:
- CAC = 0 does not exclude non-calcified plaque. Young patients with diabetes, severe hyperlipidemia, or familial hypercholesterolemia may have significant soft plaque burden with a CAC of 0. The zero score event rate is extremely low overall but does not confer absolute protection.
- Score variability between scans. Agatston scores show interscan variability of approximately 15–20% due to cardiac motion, slice selection, and software differences. Serial CAC scores should be compared with caution unless the variability exceeds ~2.5× the square root of the initial score (a threshold method for defining real progression).
- Radiation dose. Non-contrast cardiac CT for CAC scoring typically delivers 1–3 mSv of effective dose. Prospective gating with low-dose protocols can achieve <1 mSv.
- Not a screening tool for all populations. CAC scoring is validated in intermediate-risk adults (typically 40–75 years). It is not recommended as primary screening in asymptomatic low-risk patients. It is not a substitute for coronary CT angiography (CCTA) when anatomic disease assessment is needed.
- Race/ethnicity differences. MESA data shows significant variation in CAC prevalence by race/ethnicity. Asian Americans have lower CAC prevalence than non-Hispanic whites at the same age, while Hispanic Americans also have lower median scores. Percentile tables from MESA should ideally be race/ethnicity-specific.
CAC Score and Statin Decision-Making: A Practical Guide
The most impactful use of CAC scoring is in the "statin decision zone" — patients with 10-year ASCVD risk of 7.5–20% who are uncertain about initiating statin therapy. The 2018 ACC/AHA guidelines explicitly recommend CAC scoring as a decision aid in this population. The algorithm:
- CAC = 0: Defer statin. Reassess in 5–10 years unless new risk factors emerge. Communicate the excellent prognosis associated with zero score.
- CAC 1–99: Consider statin; clinical judgment required. Score at this level tilts toward statin initiation, especially if >75th percentile for age/sex.
- CAC ≥100 or ≥75th percentile for age/sex: Initiate statin therapy. This threshold represents a clear tipping point in ACC/AHA guidelines.
- CAC >400: High-intensity statin, aspirin consideration, and comprehensive cardiovascular risk management. Strongly consider cardiology referral.
Beyond statin decisions, CAC scores above 100 may trigger intensified management of hypertension, diabetes, and lifestyle factors, and may inform shared decision-making about other preventive therapies including PCSK9 inhibitors for very high-risk patients.
References
Agatston AS, et al. Quantification of coronary artery calcium using ultrafast computed tomography. J Am Coll Cardiol. 1990;15(4):827–832.
Grundy SM, et al. 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol. J Am Coll Cardiol. 2019;73(24):e285–e350.
McClelland RL, et al. Distribution of coronary artery calcium by race, gender, and age: Results from the Multi-Ethnic Study of Atherosclerosis (MESA). Circulation. 2006;113(1):30–37.
Blaha MJ, et al. Coronary artery calcium scoring in clinical practice. JACC: Cardiovascular Imaging. 2021;14(9):1765–1780.
Blankstein R, et al. Coronary Artery Calcium: A Practical Guide for Clinical Decision Making. AHA/ACC Scientific Statement. Circulation. 2021;144(21):e493–e512.