Cholesterol testing (or lipid testing) checks the levels of cholesterol in your blood to see if lifestyle changes or medicine are needed to keep you healthy. High levels of cholesterol can clog up your blood vessels, and this can lead to heart attacks or strokes.
Cholesterol is a type of fat found in every cell in your body. Your body uses cholesterol as an essential building material. It's carried around your body in your bloodstream surrounded by special proteins. Together they are called lipoproteins.
Low density lipoproteins (LDL) carry cholesterol and other fats to cells all over your body. If you have too much LDL, cholesterol can build up in the walls of your arteries and increase your risk of heart disease and stroke. High density lipoproteins (HDL) pick up cholesterol and other fats from your cells and bloodstream (including the walls of your arteries) and takes it back to your liver where it's re-used or removed from your body. Having too little HDL also means cholesterol can build up in the walls of your arteries.
Even though the balance of lipoproteins in your bloodstream can be more important than the total amount of cholesterol, having an unhealthy balance is usually known as high cholesterol.
Cholesterol is measured along with another type of fat found in your blood called triglycerides. You get these from food and they're used to store energy. Together these tests are called a lipid test or profile.
Read more about what cholesterol is.
Test results
Your cholesterol test results will provide levels of:
- total cholesterol (TC)
- low-density lipoprotein cholesterol (LDLC) – often known as 'bad cholesterol'
- high-density lipoprotein cholesterol (HDLC) – often known as 'good cholesterol'
- triglycerides
- total cholesterol/HDLC ratio.
When you have a cholesterol test, ask your healthcare provider to explain the results to you
There are guidelines for target cholesterol levels in different people.
These targets depend on your risk of getting heart disease or having a stroke – this can be found out by doing a heart risk assessment.
- For example, if you have already had a stroke or heart attack, you're at a higher risk of having another, so your targets for LDL cholesterol and total cholesterol will be lower than for someone who has a low risk of having a stroke or heart attack.
- High cholesterol levels can be an early warning to make lifestyle changes (eg, exercising more and eating more healthily) to lower your risk of cardiovascular disease. Read more about high cholesterol.
- Based on your risk and your cholesterol results, your healthcare provider will assess if you need to take cholesterol lowering medicines.
- If you're taking cholesterol lowering medicines, your cholesterol results can tell you how well your medicines are working. Depending on your cholesterol target, your healthcare provider will assess your dose.
Video: What should my cholesterol levels be?
This video helps explain cholesterol targets. Note that it was made in the UK and in Aotearoa New Zealand cardiovascular risk is measured as a 5-year risk of having a heart attack or stoke rather than a 10-year risk.
(British Heart Foundation, UK, 2018)