How Is Cholesterol Measured?
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How is the test performed?
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To have your cholesterol measured, you need a blood sample drawn. Your family doctor can conduct this test. The blood is usually drawn from a vein in the arm. An elastic band is wrapped around the upper arm so that the veins in the arm will fill with blood. Then a needle is inserted in the vein, and blood is collected in a vial or syringe. The procedure can be done quickly and without causing much pain. The blood sample is then analyzed in a laboratory to measure the amount of cholesterol and triglycerides in the blood. A cholesterol test is also called a lipid panel or a lipid profile. Cholesterol values are measured as total cholesterol, high-density lipoprotein (HDL or good) cholesterol, low-density lipoprotein (LDL or bad) cholesterol and triglycerides. Your doctor should let you know ahead of time if you need to fast (avoid all food, drinks and medications for up to 12 hours) before the test. The LDL (bad) cholesterol value is affected by what you consume just before the test.
Who should get the test?
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The American Heart Association recommends that adults over age 20 should have a fasting lipoprotein profile (HDL cholesterol, LDL cholesterol and triglycerides) every five years. It is important to get your cholesterol checked regularly, especially if you have a family history of high cholesterol or heart disease, are overweight, are physically inactive, have diabetes, or eat a high-fat diet. These factors can increase your risk of high cholesterol and heart disease. If your cholesterol tests at a high level, your doctor may recommend that you be tested more frequently than every five years. Even if you get test results indicating you have high cholesterol, it is possible to lower your cholesterol. Lifestyle changes, such as quitting smoking, exercising and eating a healthy diet, can have a positive affect on your cholesterol. Your doctor might also prescribe medicine to lower your cholesterol.
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What do the results mean?
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It is important to have your cholesterol measured because cholesterol cannot dissolve in the blood. When there is too much LDL (bad) cholesterol, it can build up on the artery walls leading to the heart and brain. Narrowed arteries, over time, increases your risk of having a heart attack or stroke. High cholesterol usually does not cause obvious symptoms, so having the cholesterol test done on a regular basis is a helpful tool in diagnosing heart disease. In the United States, cholesterol is measured in milligrams per deciliter (mg/dL) of blood. In Canada and many European countries, cholesterol is measured in millimoles per liter (mmol/L). The American Heart Association's website provides general guidelines for measuring cholesterol at americanheart.org/presenter.jhtml?identifier=183.
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