A cholesterol test, also called a lipid profile test, measures your cholesterol and triglyceride levels using a blood sample. High cholesterol or triglyceride levels can increase your risk of heart disease. There are no symptoms for high cholesterol so regular checks are recommended once you’re 20 years old.
- What is cholesterol?
- Why you should measure your cholesterol
- How to measure your cholesterol
- What does a cholesterol test measure?
- Advanced cholesterol testing
What is cholesterol?
Cholesterol is a type of fat that’s produced by your body. You need cholesterol to make hormones, vitamin D, and bile (helps you digest food).
Why you should measure your cholesterol
Your body makes all the cholesterol it needs but there are a number of things that can raise it to an unhealthy level. These are:
- eating foods high in cholesterol, saturated fats, and trans fats can increase your levels
- lack of exercise
- drinking too much alcohol
- a genetic condition called familial hypercholesterolaemia
If your cholesterol gets too high it’s called hyperlipidemia. This increases your risk of heart disease.
There aren’t any signs of high cholesterol until something goes wrong, like a heart attack or stroke. So checking your cholesterol regularly is recommended once you’re 20 years old. Over half of UK adults have high cholesterol.
How to measure your cholesterol
You can measure your cholesterol with a blood test. This can done be done either by collecting a finger-prick or venous (taken from a vein) sample.
What does a cholesterol test measure?
Your cholesterol test, sometimes called a lipid profile test, will look at the different types of fats in your blood. This includes HDL “good” cholesterol, LDL ”bad” cholesterol, and triglycerides. The ideal ranges are:
- LDL cholesterol — ideally this should be below 3 mmol/L
- HDL cholesterol — ideally this should be above 0.9 mmol/L
- triglycerides — ideally this should be below 1.7 mmol/L
- total cholesterol (HDL + LDL + triglycerides) — ideally this should be below 5 mmol/L
- cholesterol ratio (total cholesterol/HDL) — ideally this should be below 4 mmol/L
Advanced cholesterol testing
An advanced cholesterol test isn’t common but if you have one it will look at your LDL particle size and the main protein in lipoproteins called apolipoprotein.
If you have more small, dense LDL particles it can mean you’re at an increased risk of heart disease. So even if your total and LDL cholesterol isn’t particularly high, if you have a lot of smaller LDL particles you could be at an increased risk of heart disease. Large and fluffy LDL particles aren’t thought to be as harmful, they might even be protective in some cases.
Apolipoprotein B (apoB) is the main protein found in LDL cholesterol. Each LDL particle has one apoB so it’s another way to measure how many LDL particles you have. Some tests will also check apolipoprotein A-1, the main protein found in HDL cholesterol.
The techniques required to test your LDL particle size is very technical so it isn’t commonly tested for. But it’s usually possible to predict particle size by looking at your triglycerides and HDL cholesterol ratio. Another great way to assess your heart health is by measuring the inflammation in your body with a CRP test.
Allaire, J., Vors, C., Couture, P., & Lamarche, B. (2017). LDL particle number and size and cardiovascular risk: anything new under the sun?. Current opinion in lipidology, 28(3), 261-266.
Hokanson, J. E. (1998). Hypertriglyceridemia as a cardiovascular risk factor. The American journal of cardiology, 81(4), 7B-12B.
Howard, B. V., Robbins, D. C., Sievers, M. L., Lee, E. T., Rhoades, D., Devereux, R. B., … & Howard, W. J. (2000). LDL cholesterol as a strong predictor of coronary heart disease in diabetic individuals with insulin resistance and low LDL: The Strong Heart Study. Arteriosclerosis, thrombosis, and vascular biology, 20(3), 830-835.
Palazhy, S., Kamath, P., & Vasudevan, D. M. (2014). Estimation of Small, Dense LDL particles using equations derived from routine lipid parameters as surrogate markers. Biochemistry and Analytical Biochemistry, 3(1), 1.