What a coronary calcium scan actually is

A CAC scan is a low-radiation CT scan that measures the amount of calcified plaque inside the coronary arteries. It's a 5–10 minute scan, no contrast, no IV, and typically costs $100–250 out of pocket if not covered by insurance. The output is a single number — your Agatston score — that estimates calcified plaque burden. A score of 0 means no calcified plaque was detected; higher scores indicate progressively more.

What the scan does well: it provides direct, image-based evidence of plaque rather than relying on indirect risk markers like cholesterol, blood pressure, or family history. What it doesn't do: detect soft (non-calcified) plaque, which is more common in younger adults and in people with very high LDL or Lp(a). A CAC of 0 in someone with significant lipid abnormalities is reassuring but not a guarantee of clean arteries.

When the AHA's framework actually says yes

The 2018 ACC/AHA cholesterol guidelines and subsequent updates support CAC scanning for adults 40–75 in the borderline-to-intermediate risk band, where the medication decision is genuinely uncertain. A 0 score can defer statin therapy you'd otherwise consider. A score above 100 (or any score above your age-and-sex 75th percentile) tightens the case for medication. The decision tool above implements that logic plus risk-enhancers like family history and elevated Lp(a).

Where the framework says no: in symptomatic patients (a CAC scan isn't the right workup for chest pain — that's a stress test or CT angiogram), in adults who'd take the same action regardless of result, and in people already on optimized therapy where the result wouldn't change the plan. The tool routes those cases away from the scan because spending money on imaging that won't change behavior is rarely worth it.

How to actually get the scan

Most large hospital systems and standalone imaging centers offer CAC scans on a self-pay basis, often without a physician order. Search "coronary calcium scan near me" — you'll find $100–$250 cash-price options at most major US metros. If you'd prefer to go through your physician (which lets the result land directly in your medical record), use the script the tool generates above. Most clinicians who don't initially recommend the scan will order it on patient request, especially with a clear rationale.

If your doctor pushes back, the legitimate concerns are usually radiation exposure (modern CAC scans are about 1 mSv, less than a mammogram) and incidental findings (true but uncommonly clinically meaningful). Both are reasonable to weigh; neither is a hard "no" for a borderline-risk adult.

After your result

If your CAC is 0 and the rest of your panel is reasonable, you've earned a real piece of reassurance — and a re-imaging conversation in 3–5 years if anything in your risk profile shifts. If your CAC is 1–99, you're in the conversation about whether (or how aggressively) to medicate. If your CAC is 100+, the conversation has usually shifted to which therapy and what intensity, with a full lipid panel review guiding what to target. Bring the result to your clinician along with the rest of your numbers — the integrated picture is what matters.

Frequently asked

Is the radiation worth worrying about?
The radiation dose for a modern CAC scan is roughly 1 mSv — comparable to about 4 months of natural background radiation, less than a mammogram, and far less than a standard chest CT. For a single scan as an adult, the cancer risk is negligible.

Can a CAC of 0 still mean I have heart disease?
It can. CAC measures calcified plaque only. Soft plaque (the kind that's more likely to rupture acutely) doesn't show up. In adults with very high LDL or elevated Lp(a), a CAC of 0 is reassuring but not absolute.

Should I rescan, and how often?
If your initial scan is 0 and your risk profile is stable, every 3–5 years is reasonable. If it's positive, the rescan logic depends on what therapy you're on and how your risk picture is evolving. Discuss timing with your clinician at the result review.

Educational tool. Not medical advice. Logic follows the 2018 ACC/AHA cholesterol guidelines and the 2024 USPSTF / SCCT statements on CAC scoring. See methodology.