Cholesterol test
Note: this site is for informational purposes only. To view test results or book a test, use the NHS app in England or contact your GP.
This test measures the total level of cholesterol in your blood. Cholesterol is a fatty substance your body needs, but too much can increase your risk of heart disease and stroke.
Who needs this test?
High cholesterol increases your risk of heart disease and stroke. Excess cholesterol can build up in your artery walls, making them narrower and stiffer. This makes it harder for blood to flow through.
Your GP should offer you an NHS Health Check every five years between ages 40 and 74, which includes a cholesterol test.
You may need this test if you:
- have a family history of high cholesterol or heart disease
- are overweight
- have diabetes or high blood pressure
- smoke
- have already had a heart attack, stroke, or heart disease
- are taking medication to lower your cholesterol (to check if it’s working)
- have a close relative with familial hypercholesterolaemia (an inherited condition causing very high cholesterol)
Important: for the most accurate results, have your cholesterol tested by a healthcare professional rather than using a home cholesterol test.
Preparing for your test
A blood sample is taken from a vein in your arm, or sometimes by a finger-prick.
No special preparation is needed. You can eat and drink normally before the test. You don’t need to fast (not eat).
Sometimes your doctor may request a full lipid profile alongside your cholesterol test. If this happens, you may be asked to fast for 8 to 12 hours before the test. Your doctor will tell you if this is necessary.
Understanding your results
Your doctor will explain your results and what they mean for you. Understanding your cholesterol level is an important step in looking after your heart health.
What the test measures
The test measures your total cholesterol – the overall level of cholesterol in your blood. Cholesterol is a fatty substance your body needs to build cell membranes, make hormones, and produce bile acids that help digest food. Your body makes cholesterol in your liver, and you also get it from food.
Cholesterol travels through your blood attached to proteins. These combinations are called lipoproteins. There are different types of cholesterol, and your total cholesterol test shows the combined level of all these types.
What your cholesterol level results mean
Lower cholesterol levels usually mean lower risk of heart disease and stroke. However, your cholesterol level is just one risk factor among many.
- Total cholesterol should be below 5.0 mmol/L.
- Non-HDL cholesterol should be below 4.0 mmol/L.
- LDL cholesterol should be below 3.0 mmol/L.
- HDL cholesterol should be above 1.0 mmol/L for men, and above 1.2 mmol/L for women.
- TC:HDL ratio should bebelow 6 (the lower, the better).
What does ‘mmol/L’ mean?
Cholesterol levels are measured in mmol/l, which stands for millimoles per litre. A millimole is equal to one thousandth of a mole, a tiny unit of measurement used in chemistry.
If your total cholesterol is high
High cholesterol means you have more cholesterol in your blood than your body needs. This can happen because of:
- eating too much saturated fat
- an inherited tendency towards high cholesterol (runs in families)
- being overweight
- not being physically active
- smoking
- drinking too much alcohol
- certain medical conditions (underactive thyroid, kidney disease, liver disease)
- some medications (corticosteroids, beta blockers, some contraceptive pills, thiazide diuretics, oral retinoids, phenytoin)
Important: high cholesterol on its own doesn’t cause symptoms. You can feel perfectly well and still have high cholesterol. This is why testing is important.
If your total cholesterol is very high (above 7.5 mmol/L)
Very high cholesterol may suggest familial hypercholesterolaemia – an inherited condition that runs in families. People with this condition have cholesterol levels that are high from birth.
If your doctor suspects this, they may:
- ask about your family history
- arrange genetic testing
- refer you to a specialist
- recommend your close relatives get tested
Understanding your risk
Your cholesterol level is important, but it’s not the only factor that affects your heart disease risk. Your doctor considers:
- your age
- whether you smoke
- your blood pressure
- whether you have diabetes
- your family history of heart disease
- your ethnicity
- whether you’re overweight
Your doctor can use tools like QRISK3 to calculate your overall risk of heart attack or stroke in the next 10 years. This helps them recommend the right treatment for you.
Reference ranges
Reference ranges can vary slightly between laboratories. Your test results will show the reference range used by your laboratory.
The ranges may also differ based on your age and sex. Your doctor will interpret your results taking these factors into account.
Your cholesterol level can vary by up to 10% from one month to another. This is normal biological variation – your metabolism naturally fluctuates. Cholesterol levels also tend to increase slightly with age.
For this reason, if your cholesterol is high, your doctor may ask you to have a second test a few weeks or months later before starting treatment. Treatment is based on the average of these results.
- an illness
- surgery
- an injury
- a heart attack
- pregnancy
- a stressful event
Cholesterol levels can be temporarily low or high during these times. Wait at least six weeks for an accurate result.
Questions to ask your doctor
What happens next
Your doctor will discuss your results with you and agree on next steps together. What happens depends on your cholesterol level and your overall risk of heart disease.
Lifestyle changes
These are usually the first step. If your cholesterol is high your doctor may recommend:
- eating a healthy diet low in saturated fat
- increasing foods that lower cholesterol (vegetables, oats, soya, nuts, and spreads with plant stanols or sterols)
- losing weight if you’re overweight
- being more physically active
- stopping smoking
- drinking less alcohol
Medication
If lifestyle changes alone don’t lower your cholesterol enough, or if your risk is high, your doctor may prescribe medication.
What are triglycerides?
Triglycerides are a type of fat. They are the major storage form of fats and a key source of energy in the diet. They are found in foods that we eat, for example in meat, dairy products and cooking oils.
Follow-up testing
Your doctor will arrange regular cholesterol tests to check if treatment is working. How often depends on your individual situation.
Referral to a specialist
If your cholesterol is very high or you have familial hypercholesterolaemia, you may be referred to a lipid specialist.
Learn more about lowering cholesterol
Get detailed guidance on preventing heart disease and lowering cholesterol through diet and lifestyle.
About high cholesterol
Cholesterol is essential for your body to function, but too much cholesterol in your blood increases your risk of cardiovascular disease (heart disease and stroke).
When excess cholesterol builds up in your artery walls, it narrows the arteries and makes them stiffer. This is called atherosclerosis and can reduce blood flow to your heart, brain and other parts of your body.