Cholesterol testing

What is cholesterol?

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 take it back to your liver where it is re-used or removed from your body. Having too little HDL also means cholesterol can build up in the walls of your arteries.

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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. You may not realize you have high cholesterol, as it doesn’t cause any symptoms. The only way to find out if you have high cholesterol is to have a blood test.

Read more about what cholesterol is. 

Measuring cholesterol

Cholesterol is measured along with triglycerides – another type of fat found in your blood. Triglycerides come from food and are used to store energy. Together these tests are called a lipid test or profile.

Your lipid test will provide levels of:

•  low-density lipoprotein (LDL) cholesterol – sometimes known as 'bad cholesterol'
• high-density lipoprotein (HDL) cholesterol – sometimes known as 'good cholesterol'
• triglycerides
• total cholesterol (TC)
• total cholesterol/HDL ratio.

Knowing your cholesterol level helps your healthcare provider to assess your overall heart and blood vessel health and see if any lifestyle change or other treatment is needed.

As part of a cardiovascular risk check

Having high cholesterol increases your risk of heart disease and stroke, so a cholesterol test is usually done as part of a cardiovascular risk check or heart risk assessment. These checks usually start when you're 30 to 55 years of age, depending on your risk, and continue until you turn 70. 

• The results of your lipid tests are used with other risk factors such as your blood pressure and whether you smoke or have diabetes to help decide if you need treatment.
• Knowing your cholesterol level helps your healthcare provider to assess your overall heart and blood vessel health to see if any lifestyle changes or other treatment is needed. Read more about when you might need a cardiovascular risk assessment.
• How often you need to have your cholesterol levels checked will depend on your personal risk of heart attack and stroke. People with a higher risk will need to have their cholesterol checked more often. Your healthcare provider will talk with you about this after you’ve had your first cardiovascular risk check.

If you are taking medicines to lower your cholesterol

If you already have high cholesterol and start taking medicines to lower your cholesterol, then your cholesterol levels may be measured after 3 to 6 months to assess whether your medicines are working well. 

The healthy levels of cholesterol to have in your blood, are referred to as cholesterol targets. They can vary depending on several factors, including whether you've already had a heart attack or stroke.

When you're taking medicines to lower your cholesterol, you'll need to have your cholesterol checked to see if your cholesterol target has been reached.

• If your cholesterol target has not been reached, you may need to have your cholesterol levels checked every 6 to 12 months.
• If your cholesterol target has been reached, you may need to have your cholesterol levels checked every year.

If you have a family history of familial hypercholesterolaemia

There are some genetic conditions that cause very high cholesterol. If a close family member is found to have one of these conditions, you may be offered a blood test to find out if you have it too.

Checking your cholesterol levels involves a blood test. You can have a blood test at any time of day and you can eat and drink as usual beforehand. 

However, some people who have had high triglycerides in the past, may need to fast before their blood test. This means going without food and drink, except water, for about 8 hours before having the test. Your healthcare provider will let you know if you need to fast. 

• You can have your test done first thing in the morning, just before breakfast, to make fasting easier.
• You can drink water and take your normal medications – don't stop taking these unless your healthcare provider tells you to.

If you've had recent surgery, a heart attack or been unwell (eg, with influenza), it's better to wait at least 6 weeks before having the test done. This will help to get a more accurate result.

If you're taking blood-thinning medicines (eg, aspirin, dabigatran, rivaroxaban or warfarin), or have bleeding or clotting problems, tell the nurse or laboratory staff about this before the blood sample is taken.

If you're pregnant, you should wait until at least 6 weeks after the baby is born to have your cholesterol measured, as cholesterol is higher during pregnancy.

You can get a cholesterol test at a laboratory, pharmacy, or some medical centres.

• Laboratory: You can get a cholesterol test at a community laboratory where a blood sample is collected from a vein in your arm. You may need to make an appointment, check with your local laboratory. It's funded if you're eligible and the test has been requested by your healthcare provider. Some laboratories allow you to order your own blood tests if you pay for them yourself.  
• Medical centre: At some practices a nurse can take your blood sample. Have a look at your practice website to see if they offer this service. 
• Pharmacy: Some pharmacies offer a finger-prick test that measures cholesterol levels. There's a charge for this service. If your reading is high, the pharmacist will ask you to make an appointment at your medical centre.

Your healthcare provider will tell you the results of the blood tests. They may be available through your patient portal if you are signed up with one. The results are used to provide information on your overall health and your risk of heart attack and stroke. 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.

Your healthcare provider will use other cardiovascular disease risk factors such as your age, sex, blood pressure and whether you smoke or have diabetes when deciding whether treatment is needed.

Read more about cholesterol test results.