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Diagnosis - High cholesterol

High cholesterol is when you have too much of a fatty substance called cholesterol in your blood.

High cholesterol does not cause symptoms. You can only find out if you have it from a blood test.

Getting a cholesterol test

A blood sample is taken to find the amount of bad and good cholesterol and other fatty substances in your blood.

You should not eat for 10 to 12 hours before the cholesterol test. This is to make sure that all food is digested and will not affect the outcome of the test.

Your GP or practice nurse can carry out the cholesterol test. They will take a blood sample, either using a needle and a syringe or by pricking your finger.

Checking your cholesterol

Your GP may recommend that you have your blood cholesterol levels tested if you:

  • have been diagnosed with coronary heart disease, stroke, mini-stroke or peripheral arterial disease
  • are over the age of 40 – you should have your estimate of cardiovascular disease risk reviewed regularly
  • have a family history of early cardiovascular disease
  • have a family member who has a cholesterol-related condition, such as familial hypercholesterolaemia
  • are overweight or obese
  • have high blood pressure or diabetes
  • have another medical condition such as, kidney disease, an under active thyroid, or an inflamed pancreas (pancreatitis). These conditions can cause increased levels of cholesterol or triglycerides

Results of cholesterol tests

After your cholesterol test, your GP or nurse will explain your results. They will calculate the risk you have of developing heart disease or stroke within the next 10 years.

This risk is not just based on your cholesterol reading.

It also takes into account:

  • your BMI (body mass index) – which measures your weight in relation to your height
  • treatable risk factors like high blood pressure (hypertension), diabetes and other medical conditions
  • your age, sex, family history and ethnicity

Based on your results, your GP or nurse will recommend steps you can take to reduce your risk of developing cardiovascular disease.

This may include advice about making lifestyle changes. These could include eating more healthily and exercising more.

They may also recommend cholesterol-lowering medication, such as statins.

Inherited high cholesterol

People with inherited high cholesterol (familial hypercholesterolaemia), are at increased risk of developing cardiovascular disease. It's important to be diagnosed as early as possible.

If you've been diagnosed with familial hypercholesterolaemia, you'll be referred to a specialist for assessment.

Treatment will be recommended for you. Other members of your family who may be affected will also be tested.

You'll have a full review at least once a year to check how well your treatment is working. They will also assess any symptoms you may have.


Children at risk of inherited high cholesterol (familial hypercholesterolaemia) will be tested by the time they reach 10 years old.

This is because any signs of CVD, such as thickening of the carotid artery wall, will be identifiable by this age.

Early diagnosis means it's possible to recommend lifestyle changes and other treatments. These will reduce the long-term problems associated with high cholesterol. The will also improve their long-term health.

Inherited Heart Disease (PDF, 2MB, 32 pages)

Content supplied by the NHS and adapted for Ireland by the HSE

Page last reviewed: 24 March 2021
Next review due: 24 March 2024

This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.