Carotid artery scan, cholesterol test or calcium score: which tells you most?

The short answer

A cholesterol test shows the risk factors in your blood. A carotid artery scan shows whether your neck arteries have started to thicken or form plaque. A coronary calcium score uses a CT scan to show calcified plaque in your heart arteries. Each answers a different question, so the best choice depends on your age, risk factors and what you’d do with the result.

People often ask me which heart test is “best”. The honest answer is that they measure different stages of the same process.

What does each test measure?

Think of atherosclerosis as a story told in three chapters:

Risk factors. What’s in your blood and your lifestyle that could damage arteries. Shown by cholesterol, Lp(a), blood sugar and blood pressure.
Early artery changes. Thickening and soft plaque that haven’t caused symptoms. Shown by a carotid artery scan.
Established, calcified plaque. Plaque that has hardened in the heart arteries. Shown by a calcium score.

How do they compare?

	Cholesterol blood test	Carotid artery scan	Coronary calcium (CAC) score
What it looks at	LDL, HDL, triglycerides and more	Neck artery wall thickness and plaque	Calcified plaque in heart arteries
How it’s done	Blood test	Ultrasound	CT scan
Radiation	None	None	A low dose
Sees soft, early plaque?	No	Yes	No, only calcified plaque
Typical UK cost	Usually free via your GP	£456 in my clinic	Private scans from about £395 to £400 (Scan.com)
Best for	Everyone, as a baseline	Early changes, often in people under 60 or with inflammatory risk	Refining risk in older adults deciding about statins

What does a cholesterol test tell you?

A standard lipid test measures total cholesterol, LDL, HDL and triglycerides. Your GP combines these with your age, blood pressure, smoking and other factors to estimate your 10-year risk, usually with a tool called QRISK3.

It’s an essential starting point, but it describes risk, not what’s happening in your arteries. I often add:

ApoB, which counts the cholesterol-carrying particles that cause damage
Lp(a), which is mainly genetic and missed by standard tests. Read What is Lp(a), and should you get it tested?
HbA1c and fasting insulin, for blood sugar
hs-CRP, for inflammation

What does a carotid artery scan tell you?

It shows the artery wall itself. It can pick up soft plaque, the earlier and more unstable kind, which a calcium score can’t. That makes it especially useful for younger people and women, whose plaque is less likely to be calcified yet. It’s quick, painless and radiation-free. The European Society of Cardiology doesn’t recommend wall thickness alone for routine risk assessment, but recognises carotid plaque as a possible risk modifier (ESC 2021). More in Should you have a carotid artery scan if you feel well?

What does a coronary calcium score tell you?

A CAC score uses a quick CT scan to measure calcium in the heart’s arteries. A score of zero in an older adult is reassuring. A high score signals established disease. It’s widely used to help people at intermediate risk decide about statins. It involves a low dose of radiation, and it can’t see soft plaque, so a zero score in a younger person doesn’t rule out early disease.

Which test should you choose?

Everyone: know your blood pressure, cholesterol, blood sugar and, at least once, your Lp(a) (HEART UK).
If you’re under about 60 and have risk factors, or an inflammatory condition, or are going through menopause: a carotid scan often adds the most.
If you’re older and on the fence about a statin: a calcium score is very useful, and is often combined with your GP’s assessment.
Strong family history or high Lp(a): imaging, either carotid or calcium, can help clarify your personal risk.

Common questions

Is a calcium score better than a carotid scan?

Neither is better overall. A calcium score looks at the heart’s arteries but only sees calcified plaque, and uses radiation. A carotid scan sees earlier, soft plaque without radiation, but in the neck rather than the heart.

Can I have normal cholesterol and still have plaque?

Yes. Lp(a), inflammation, blood sugar, blood pressure and genetics all contribute, which is why imaging can be helpful for some people.

Does a calcium score of zero mean I’m safe?

In older adults it means low short-term risk. In younger people, soft plaque may be present that a calcium score can’t see.

Can my GP arrange these tests?

Basic cholesterol tests, yes. Carotid scans are arranged on the NHS when there’s a clinical reason. Calcium scores are mainly private in the UK.

Want help deciding? Book a free discovery call.