High Cholesterol
Examinations and Tests
You will need a blood test to check whether you have high cholesterol.
- A total cholesterol test measures whether your cholesterol is high or low. You can have this test done at any time, even if you recently had a meal or snack.
- A lipoprotein analysis is a more thorough test. It measures your total cholesterol as well as your LDL, HDL, and triglyceride levels. It is called a fasting test because you are not supposed to eat for 9 to 12 hours before having your blood drawn.
Too much cholesterol in your blood increases your chances of having coronary artery disease (CAD), a heart attack, or a stroke. Although knowing your total cholesterol level is important, a lipoprotein test will help your doctor make certain decisions about your treatment. Knowing the levels of your good cholesterol (HDL), bad cholesterol (LDL), and triglycerides will help your doctor decide whether to prescribe medicine right away or whether you first can try making changes in your diet and lifestyle to lower your cholesterol.
If you do not have CAD or a health condition that increases your chance of having CAD, the following will help you understand the results of your test. If you have CAD or a health condition that increases your chance of CAD, talk to your doctor about which cholesterol and triglyceride target levels are best for you.
Total cholesterol Best Less than 4.1 millimoles per litre (160 milligrams per decilitre)
Borderline high 4.1 mmol/L to 6.1 mmol/L (160 mg/dL to 240 mg/dL)
High 6.2 mmol/L (240 mg/dL) or above
LDL (bad) cholesterol Best Below 2.5 mmol/L (100 mg/dL)
Near best 2.6 to 3.5 mmol/L (100 to 135 mg/dL)
Borderline high 3.6 mmol/L to 4.0 mmol/L (135 to 159 mg/dL)
High 4.1 to 4.9 mmol/L (160 to 190 mg/dL)
Very high 5.0 mmol/L (190 mg/dL) and above
HDL (good) cholesterol Best 1.5 mmol/L (60 mg/dL) or higher protects against heart disease
Good 1.0 mmol/L (40 mg/dL) and above
Bad Below 1.0 mmol/L (40 mg/dL)
Triglycerides Borderline high 1.7 to 6.0 mmol/L
High 6.0 mmol/L or higher
Your doctor may recommend different target levels for you, depending on your overall health and any special health concerns you may have.
During your doctor visit, it will be important to discuss other things that increase your risk for heart problems, such as smoking, diabetes, high blood pressure, and a family history of high cholesterol and heart attack. The Canadian Diabetes Association recommends an LDL level of 2.0 mmol/L or less if you have diabetes.2
You may need other tests to determine whether another health problem, such as low thyroid, is causing your high cholesterol. Some medicines may also cause high cholesterol, so it is important to tell your doctor about everything you take.
Along with your cholesterol levels, your doctor will use this information to determine your risk for coronary artery disease (CAD) and heart attack. If you have a high risk of heart disease, or if you already have heart problems, your doctor will be more likely to prescribe medicine. For more information, see the topic Coronary Artery Disease.
If you have high cholesterol or high blood pressure, you should get tested regularly for diabetes. Studies show that finding and treating diabetes early can lower the risk of heart attack.3
The American Heart Association (AHA) and the U.S. Centers for Disease Control and Prevention (CDC) recommend C-reactive protein (CRP) testing for some people who are at risk for getting coronary artery disease. There are two types of CRP tests: the older CRP measurement and a newer, high-sensitivity CRP, often called cardiac CRP. The high-sensitivity test helps find out the chances of a having a sudden heart problem, such as a heart attack. In Canada, cardiac CRP tests for CAD currently are only used in research studies and are not yet widely available.
Two studies on CRP levels and statin treatment show that testing CRP levels may help predict heart attack risk even when a person has a normal or low level of LDL cholesterol.4, 5 Another study found higher CRP levels in people who have health problems related to metabolic syndrome.6 These problems include too much fat around the waist, elevated blood pressure, high triglycerides, elevated blood sugar, and low HDL cholesterol.
Ask your doctor if CRP testing would be helpful in guiding your treatment.7
More information
Early Detection
Some doctors and health organizations recommend that everyone older than 20 be checked for high cholesterol. How often you should be checked depends on whether you have other health problems and your overall chance of heart disease. For more information, see when to have a cholesterol test.
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| Author: | Douglas Dana Ralph Poore | Last Updated: November 13, 2006 |
| Medical Review: | Caroline S. Rhoads, MD - Internal Medicine Tom Bailey, MD - Family Medicine Neil J. Stone, MD, FACC, FACP - Internal Medicine, Cardiology | |
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