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Cholesterol Test

Also known as: Blood cholesterol; total cholesterol
Related tests: HDL, LDL, Triglycerides, Lipid profile

The Test

How is it used?

Cholesterol is different from most tests in that it is not always used to diagnose or monitor a disease but is used to estimate the risk of developing a disease — specifically heart disease. Because high blood cholesterol is associated with hardening of the arteries, heart disease and a raised risk of death from heart attacks, cholesterol testing is considered a routine part of preventive health care.

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When is it requested?

Cholesterol testing is recommended when you have established heart disease (angina, heart attack), or if there is a family history of high cholesterol, or of heart disease at an early age; if you have risk factors which put you at an increased chance of developing heart disease, such as diabetes, high blood pressure, or you are a smoker. Cholesterol testing is also performed if you are following a recommended diet or taking drugs to lower your cholesterol level, to monitor your response to treatment. Total cholesterol may be measured alone or in combination with other tests including HDL, LDL, and triglycerides — often called a lipid profile.

For those under 20 years of age and at low risk, cholesterol testing is not requested routinely. However, screening for high cholesterol as part of a lipid profile is recommended for children and youths who are at increased risk of developing heart disease as adults. Some of the risk factors are similar to those in adults and include

  • Family history. History of high cholesterol or heart disease in close relatives particularly if occurring before age 55 in women or 65 in men. If the family history is not known, a cholesterol test is recommended, especially if other risk factors are present.
  • Being overweight or obese. When the youth’s body mass index (BMI) is elevated, cholesterol testing is recommended.
  • Consuming excessive amounts of cholesterol and saturated fats
  • Diabetes mellitus
  • High blood pressure (hypertension)
  • Smoking cigarettes

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What does the test result mean?

Looking for reference ranges?

The cholesterol level measured in your blood will be considered along with other risk factors for heart disease (high blood pressure, smoking etc.) when assessing your overall risk of developing heart disease. This overall assessment is what will be used to decide whether or not you require further treatment in the form of dietary changes or drugs to lower your cholesterol level.
If you are taking treatment to lower your cholesterol, the target is to lower your total cholesterol to a value less than 4 mmol/L, with a fall of around 20-25%.

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Is there anything else I should know?

Cholesterol should be measured at a time when a person has not recently been taken ill. Blood cholesterol is temporarily low during acute illness, immediately following a heart attack, or during stress (like from surgery or an accident). You should wait at least 6 weeks after any illness to have cholesterol measured.  

There is some debate about whether a very low cholesterol level is harmful. 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.

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.

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