Your health care provider may send you for cholesterol tests, either as a part of a standard check-up or because he or she suspects you may be at risk for developing heart disease. But do you know what the cholesterol test results actually mean? Read on to learn how to interpret the numbers.
Why Do I Need a Cholesterol Test?
Cholesterol is a waxy, fat-like substance. Your liver makes all the cholesterol your body needs. But you take in more cholesterol from certain foods, such as those from animals. If you have too much cholesterol in your body, it can build up in the walls of your arteries (as "plaque") and eventually harden. This process, called atherosclerosis, actually narrows the arteries, making it harder for blood to travel through the vessels.
Unfortunately, high cholesterol doesn't cause symptoms. In later stages of atherosclerosis, though, you may suffer angina -- severe chest pain from lack of blood flow to the heart. If an artery gets totally blocked, a heart attack results. A routine blood cholesterol test is a far better way of finding out what your cholesterol level is.
What Does a Cholesterol Test Measure?
In addition to measuring the total cholesterol in your blood, the standard cholesterol test (called a "lipid panel") measures three specific kinds of fat:
- Low-density lipoproteins (LDL). This is the "bad cholesterol," the main cause of plaque build-up, which increases your risk for heart disease. In general, the lower the number, the better. But LDL cholesterol is only one part of a larger equation that measures a person’s overall risk of having a heart attack or stroke. For years, guidelines focused on specific target numbers for individuals to achieve to lower their risk. The most recent guidelines focus on a person’s overall risk and, based on that risk, recommend a certain percentage of LDL reduction as one part of a strategy for preventing serious heart and vascular problems.
- High-density lipoproteins (HDL). This is the "good cholesterol." It transports bad cholesterol from the blood to the liver, where it is excreted by the body. Your HDL is another part of the equation that identifies the risk of a cardiovascular event. In general, the higher the number the better, although, as with LDL, the emphasis has shifted from specific target numbers to strategies for reducing the overall risk.
Triglycerides. Another type of fat in the bloodstream, triglycerides are also linked to heart disease. They are stored in fat cells throughout the body.
What Do Cholesterol Test Numbers Mean?
If you have a lipoprotein profile, it's important to look at all the numbers from the cholesterol test, not just the total cholesterol number. That's because LDL and HDL levels are two primary indicators of potential heart disease. Use the information below to interpret your results (with the help of your doctor, of course). This will help you get a better idea about your risk for heart disease.
Total blood cholesterol level:
- High risk: 240 mg/dL and above
- Borderline high risk: 200-239 mg/dL
- Desirable: Less than 200 mg/dL
LDL cholesterol levels:
190 mg/dL and above represents a high risk for heart disease and is a strong indicator that the individual can benefit from intensive treatment, including life style changes, diet, and statin therapy for reducing that risk.
For LDL levels that are equal to or less than 189 mg/dL, the guidelines recommend strategies for lowering LDL by 30% to 50% depending on what other risk factors you have that can affect the health of your heart and blood vessels.
- High risk: Less than 40 mg/dL
- Very high risk: 500 mg/dL and above
- High risk: 200-499 mg/dL
- Borderline high risk: 150-199 mg/dL
- Normal: Less than 150 mg/dL
How Do I Prepare for My Cholesterol Test?
If your doctor recommends a "non-fasting" cholesterol test, the lab will look only at your total cholesterol (and sometimes your HDL) numbers. For that test, you merely need to show up at the lab and have some blood drawn. If your doctor suggests a "fasting" cholesterol test (also called a "lipid profile"), the lab will analyze your levels of LDL, HDL, triglycerides, and total cholesterol. For that test, you will need to fast nine to 12 hours before the blood test.
Sometimes a doctor will ask you to do a non-fasting cholesterol test first. Depending on the results, he or she may then send you back for the more complete lipid profile.
How Will My Doctor Use Results From My Cholesterol Test?
After reviewing your blood test, The doctor will also consider other risk factors you might have for heart disease, including:
- Your family history
- Blood pressure and whether or not you’re being treated for high blood pressure
- Activity level
- Smoking status
- History of diabetes
Then, your doctor will talk with you about your level of risk and the potential benefit to be derived by taking steps that include changes in your level of activity and diet as well as using medication to improve your cholesterol levels in order to reduce your overall risk.
How Often Should I Have A Cholesterol Test?
The National Cholesterol Education Program recommends adults age 20 years or older have a cholesterol test every five years. People who are at risk for heart attack may need to be checked more often.