As part of a cardiovascular health check, or if you are taking (or are about to start) treatments which lower cholesterol.
Testing for cholesterol requires a blood sample. Most often, the blood sample is collected from a vein in the arm or by a fingerprick.
To obtain an accurate result, it is better to have your cholesterol tested by a professional than to use a home cholesterol test.
No fasting is needed for a cholesterol test.
Sometimes a fasting sample is required for a full lipid profile including cholesterol.
Cholesterol is a substance that is essential for formation of cell membranes, hormones and bile acids. Cholesterol comes both from your diet and the production of cholesterol in the liver.
Cholesterol and other lipids are carried in the blood attached to proteins, forming particles known as lipoproteins.
Two different types of cholesterol are:
- LDL cholesterol is part of low density lipoprotein.This is often called bad cholesterol, because if there’s too much LDL cholesterol in your blood it can build up in the arteries, clogging them up.
- HDL cholesterol is part of high density lipoprotein.This is often called good cholesterol because it helps prevent disease by carrying cholesterol away from the cells, back to the liver, where it can be broken down and removed from the body.
Total cholesterol refers to the overall level of cholesterol.
Non-HDL cholesterol is the total cholesterol minus the HDL cholesterol and ideally should be as low as possible.
TC:HDL ratio is a ratio of HDL compared to the total cholesterol. This should be as low as possible. Above 6 is considered high.
Interpreting your results
Your cholesterol results should be interpreted in relation to other risk factors . Because of other risk factors or medical conditions, your doctor may recommend lowering your cholesterol level.
How is it used?
When is it requested?
Your GP should invite you for an NHS health check once every five years from the age of 40 to 74. The NHS health check is designed to prevent cardiovascular disease and includes a cholesterol test.
It may be checked if you have risk factors for cardiovascular disease such as:
- Family history of high cholesterol or heart disease in close relatives.
- Being overweight or obese.
- Diabetes mellitus
- High blood pressure (hypertension)
- Smoking cigarettes
It maybe checked at intervals if you have been prescribed treatments to help lower your cholesterol, such as statins.
What does the test result mean?
Cholesterol levels indicate risk and a lower level usually indicates a lower risk.
Ideal cholesterol levels in mmol/L are as follows:
Total (serum) cholesterol below 5.0
Non-HDL cholesterol below 4.0
LDL cholesterol below 3.0
HDL cholesterol above 1.0 for a man and above 1.2 for a woman
TC:HDL ratio above 6 is considered high risk - the lower this figure is the better.
Is there anything else I should know?
There is a condition which runs in families called “familial hypercholesterolaemia” in which cholesterol is usually over 7.5 mmol/L in adults.
Cholesterol is temporarily low during acute illness, immediately following a heart attack, or during stress (like from surgery or an accident). To get a true representation of your cholesterol, you should wait at least six weeks after any illness before having it measured.
In women, cholesterol is high during pregnancy. Women should wait at least six weeks after the baby is born to have cholesterol measured.
Some drugs that are known to increase cholesterol levels include oral corticosteroids, beta blockers, oral contraceptives, thiazide diuretics, oral retinoids and phenytoin.
A very low cholesterol is often seen when there is an existing problem like malnutrition, liver disease, or cancer. However there is no evidence that low cholesterol causes any of these problems.
What causes high cholesterol?
High cholesterol may be the result of an inherited disease or it may result from a diet high in saturated fats. For many people it is caused by a combination of both a high fat diet and an inherited tendency towards high cholesterol. This is why is usually helpful to have a full lipid profile checked.
What treatments are recommended if my levels are too high?
The first step in treating high cholesterol, usually due to a high non-HDL cholesterol, is adoption of a healthy diet. In particular, people are often advised to reduce saturated fat intake, and increase intake of foods which are known to lower non-HDL cholesterol, including vegetables, oats, soya, nuts, and some spreads fortified with ‘plant stanols’ or ‘plant sterols’. For advice on how to lower cholesterol through diet and lifestyle, visit the Heart UK website. If dietary changes alone do not adequately lower cholesterol, drugs may be prescribed. A class of drug called ‘statins’ is usually used first line. Statins have been around for many years and there is excellent evidence that they are effective in lowering LDL cholesterol and other forms of bad cholesterol, and have a low rate of side effects. Other drugs that are available include ezetimibe, bile acid sequestrants and fibrates. These are usually used second or third line if statins are not sufficient.
What is my risk of a heart attack if I have high cholesterol?
High cholesterol increases your risk of a heart attack. The higher the cholesterol, the higher the risk. However, many other factors also affect your risk of a heart attack, such as smoking, diabetes, age, and high blood pressure. Charts are available which enable the risk to be estimated for individuals.Your doctor can use charts and equations which use several factors to estimate your future risk of developing cardiovascular disease.
I haven't changed my diet or exercise pattern but my cholesterol has gone up since the last time it was tested. Why?
Cholesterol levels fluctuate over time. The measured cholesterol level may differ by as much as 10% from one month to another. It may go up sometimes or it may go down sometimes. These changes are called biological variation and they represent normal variability inherent in human metabolism. Cholesterol levels also tend to climb a little with age.
My doctor told me I had a high cholesterol test but instead of treating me he told me to wait a few months and test it again. Why?
Cholesterol levels fluctuate over time. A single measurement of cholesterol may not always reflect the "usual” cholesterol level. For this reason, it is advisable to have at least two different measurements several weeks to several months apart before beginning any kind of treatment. Treatment is based on the average value. It may also allow an opportunity to determine whether dietary intervention has any impact on the cholesterol level, prior to considering drug therapy.