Cholesterol is a type of fat in your blood. Most cholesterol is made by your body, but eating fatty foods can lead to high cholesterol levels in your blood. Your arteries may clog up with the fatty cholesterol and this can increase your risk of having a heart attack or stroke.
You cannot tell or feel if you have high cholesterol.
If your cholesterol level is too high your doctor may give you medication. Statins are one of the common medications given to help to lower cholesterol and reduce your risk of having a heart attack or stroke.
What else can I do to lower my cholesterol?
You may be able to reduce your cholesterol by making changes to your lifestyle such as:
Eating healthy foods, including lots of fruit and vegetables, low or reduced fat milk, lean meat, nuts and seeds.
Avoiding takeaways and deep fried foods, cakes, biscuits, pastries and chips.
Reducing red meat, cheese and butter.
Staying at a healthy weight.
Exercising regularly – being active for at least 30 minutes a day most days of the week.
These make up your 'blood lipid profile' – lipids are just another name for the fatty substances in the body and bloodstream.
What do my cholesterol test results mean?
Your doctor will advise you of the results of the cholesterol tests and what these mean in relationship to your age, sex and general health profile. According to the New Zealand guidelines an ideal lipid profile is:
total cholesterol less than 4 mmol/L *
LDL cholesterol less than 2.0 mmol/L *
HDL cholesterol greater than 1 mmol/L
total cholesterol/HDL ratio less than 4
triglycerides less than 1.7 mmol/L.
* Note: Lower targets are appropriate for people who have heart disease, diabetes or kidney disease. Check with your doctor what your target level should be.
These cholesterol results are not interpreted on their own – your doctor will take other heart risk factors into account as well. If your cholesterol level is high, you should have regular check-ups every three to six months, depending on the results and your doctor's advice.
Why is a cholesterol test useful?
A cholesterol test is not used to diagnose a disease. Instead, measuring cholesterol and knowing the levels of these lipids provides important information on your health and your long-term risk of heart disease and stroke. Together with other cardiovascular risk factors (such as blood pressure and body weight), your cholesterol results can give your doctor an overall picture of your health.
If the blood test results are not within normal limits, this 'early warning' allows you to make lifestyle changes and consider treatments to lower your future risk of heart attack and stroke. Making changes on the advice of your doctor can greatly alter your risk.
When and where do I go for the test?
Normally, your doctor will ask you to have the cholesterol test at the nearest community diagnostic laboratory, or the practice nurse may be able to take the blood sample.
If you have had recent surgery, a heart attack or been unwell (eg, influenza), it is better to wait at least six weeks before having the test done, for a more accurate result.
Pregnant women should wait at least six weeks after the baby is born to have cholesterol measured, as cholesterol is higher during pregnancy.
How is the cholesterol test carried out?
Some cholesterol tests can be conducted with a finger-prick blood sample, but more detailed testing requires a blood sample collected from a vein in the arm.
You may need to fast (go without food and most drink apart from water) for a specified period (usually at least eight hours) before taking the test. If so, you will be told in advance by your doctor or local laboratory and have your test done first thing in the morning, to minimise the inconvenience of fasting.
You should still be allowed to drink water and take your normal medications – do not stop taking these unless your doctor advises you to (eg, if the medications would interfere with the test result).
People taking blood-thinning medications (eg, aspirin or warfarin), or those with bleeding or clotting problems, should also inform the nurse or laboratory staff of this before the blood sample is taken.
This page is aimed at health professionals or those interested in more detailed information.