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.

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

While cholesterol is essential for your health, if it gets too high it might increase your risk of heart disease — putting you at risk of things like a heart attack or stroke.

There are a number of things that can raise your cholesterol to an unhealthy level:

  • eating foods high in cholesterol, saturated fats, and trans fats can increase your levels
  • lack of exercise
  • smoking
  • drinking too much alcohol
  • a genetic condition called familial hypercholesterolaemia

There aren’t any signs of high cholesterol until something goes wrong, like a heart attack. So measuring your cholesterol levels regularly is recommended.

Regular cholesterol tests are particularly important if you:

  • are overweight or obese
  • smoke
  • have a family history of high cholesterol or heart disease
  • have high blood pressure, coronary artery disease, or diabetes
  • are on medication for high cholesterol and need to track your levels

How to test your cholesterol levels

To test your cholesterol levels, you need to collect a blood sample. The two main ways to do this are to do:

  • a finger-prick blood test — you can collect a small blood sample yourself with a lancet by using our cholesterol blood test. Your results will be reviewed by a GP and are available for you to view online within 48 hours.
  • a venous blood test — or if you'd like some help, you can visit a clinic where a trained professional will use a needle to puncture a vein, usually in your arm, to collect your blood sample.

Thriva blood test kit next to lemon tea and diary

Preparing for a cholesterol test

There are a couple of things you can do before a blood test so the process is as smooth as possible:

  • drink a lot of water — being hydrated makes it easier to collect your blood sample and evidence shows that dehydration can affect your results
  • keep warm — having a hot shower or jumping on the spot for a minute makes it easier to collect a finger-prick blood sample

You might also need to fast before doing a cholesterol blood test. This is because eating a high-fat meal close to when you take your sample could raise your triglycerides for a short time.

Fasting before a cholesterol test

Ideally, you should fast before a cholesterol test. Fasting means not eating or drinking anything except water for up to 8-12 hours before your test. Doing your test in the morning can make this part of the process easier.

Fasting is important because a recent meal could affect your LDL cholesterol and triglyceride levels.

How is cholesterol measured?

Your cholesterol test, sometimes called a lipid profile test, will look at the different types of fats in your blood. This includes your total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides.

Advanced cholesterol test
Although not very common, an advanced cholesterol test will look at your LDL particle size and number and the main protein in lipoproteins called apolipoprotein. This is thought to be a better predictor of your heart disease risk rather than the total amount of LDL cholesterol you have.

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.

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 dividing your triglycerides level by your HDL cholesterol level (TG/HDL-C ratio). Another way to assess your heart health is by measuring the inflammation in your body with a CRP test.

Cholesterol test results explained

Your cholesterol results will provide you with a range of figures. It’s important to look at each one and not just your total cholesterol. In the UK, cholesterol and triglyceride levels are measured in millimoles per litre (mmol/L) of blood.

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

The reference ranges for LDL particle size is (when your results are in mmol/L) are:

  • less than 0.87 is ideal
  • above 1.74 is high risk
  • above 2.62 is very high risk

What does high cholesterol mean?

If your cholesterol levels are raised to an unhealthy level it’s called hyperlipidemia. There’s a lot of evidence from many large clinical trials showing a clear link between high cholesterol and:

  • stroke
  • heart attack
  • angina (chest pain)
  • high blood pressure
  • chronic kidney disease

Keep in mind that over half of people who have a heart attack have normal LDL cholesterol levels. Heart disease is very complex and cholesterol is only part of the picture. Your medical practitioner will also take into account many other factors like your BMI, age, sex, other medical conditions, and family history when assessing your risk for cardiovascular disease.

Managing your cholesterol

There are many things that you can do to lower your cholesterol. A healthy lifestyle is very effective at lowering or maintaining your cholesterol levels, as well as being good for your overall health. Sometimes you might need to combine lifestyle changes with medication.

Natural ways to lower cholesterol
There are lots of things you can do to lower your cholesterol naturally:

  • eat high-fibre foods, like fruits, vegetables, and whole grains
  • eat lean sources of protein, like chicken, fish, and legumes
  • eat oily fish, like salmon and mackerel
  • avoid foods high in cholesterol, saturated fats, and trans fats
  • avoid fast food and fried foods
  • exercise regularly — this can help raise your HDL “good” cholesterol
  • lose weight if you’re overweight
  • avoid drinking too much alcohol
  • don’t smoke

Fruits and vegetables in brown paper bag

Cholesterol-lowering medications
In some cases, your doctor might prescribe you medication to try to lower your cholesterol level. The most commonly prescribed medications are statins — these block your liver from producing cholesterol. Other medications can reduce the amount of cholesterol you absorb from foods.

Because medications can have side effects, it’s usually preferable to try to follow a healthy lifestyle first to lower your cholesterol. Your doctor will advise you on what’s the best treatment for you.

If medication is required then it’s still important not to just rely on them solely for reducing your cholesterol levels, continue with the lifestyle changes recommended to further reduce your risk of cardiovascular disease.

Thriva podcast: Red meat


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 lipidology28(3), 261-266.

Campbell, N. R., Wickert, W., Magner, P., & Shumak, S. L. (1994). Dehydration during fasting increases serum lipids and lipoproteins. Clinical and investigative medicine, 17(6), 570.

Hokanson, J. E. (1998). Hypertriglyceridemia as a cardiovascular risk factor. The American journal of cardiology81(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 biology20(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 Biochemistry3(1), 1.