Cholesterol Testing
What is it?
Cholesterol and triglycerides are the two major fats in the blood. Blood fats are also called lipids. Your body makes cholesterol and gets it from food, then uses it to build cell membranes and hormones. Cholesterol testing is an analysis of the cholesterol levels in a sample of your blood. High levels of cholesterol in the bloodstream can block blood flow and increase your risk of health problems such as atherosclerosis and coronary artery or carotid artery disease. These diseases increase your risk of having a heart attack or stroke. However, not all cholesterol is bad. To travel through the bloodstream, cholesterol attaches itself to certain proteins. The combination of fats and proteins are called lipoproteins. Cholesterol is carried by two types of proteins. A high level of low-density lipoproteins (LDL) increases the risk of heart disease because it leaves the fat on the inside walls of the blood vessels and deposits it in body tissues. You may have heard LDL referred to as the
"bad cholesterol". The cholesterol carried by high-density lipoproteins (HDL) lowers your risk of heart disease, and is often called
"good cholesterol". HDL actually helps your body get rid of cholesterol. Cholesterol is usually measured as total serum cholesterol. However, because the level of HDL cholesterol is so important, many doctors look at the ratio of the total cholesterol level to HDL cholesterol level to assess the risk of heart disease.
Who needs this procedure?
Adults over the age of 20 should be tested for cholesterol and HDL levels every five years. People whose total cholesterol is high, HDL is low, or who have a medical history that includes risk factors for heart disease may need to be tested more frequently with a complete lipoprotein profile. This includes total cholesterol, triglycerides, HDL, and calculated LDL. A cholesterol test is also used to evaluate a patient's fat metabolism and to help diagnose inflammation of the pancreas, liver disease, and certain thyroid disorders. People on certain mediations that inhibit the liver's ability to absorb fats may also need more frequent cholesterol testing. People who have had recent surgery, are extremely ill, have high fever, or an eating disorder should not be given cholesterol tests because the results will be
inaccurate.
How do I prepare for this procedure?
If you are having a cholesterol test, you should fast for at least 12 hours before the test. This means you may not eat anything, and may drink only water. Avoid alcohol for 24 hours before the test. Your doctor may recommend that you stop taking any medications that may affect the accuracy of the test results. However, do not stop taking any regularly prescribed medications unless your doctor tells you
to.
How is this procedure performed?
To perform a cholesterol test, a small amount of blood (5 milliliters) is withdrawn from one of your veins while you are seated. Once the blood is removed, it will be carefully labeled with information such as your name, the time and date the blood was drawn, and your doctor's name. Then, the blood will be separated in a laboratory so the levels of cholesterol and HDL, as well as any other lipoproteins, can be
measured.
What can I expect after the procedure?
You may have some slight discomfort or bruising around the area where the needle punctured your skin. Putting some pressure on the puncture site right after the needle is removed until the bleeding stops will reduce bruising. Some very sensitive people may feel slightly dizzy or faint when they stand up. Drinking some fruit juice and eating a cookie or cracker usually makes this feeling go away. Your doctor will receive the results and give them to you. What is considered a normal result depends upon your age, sex, and race, and your doctor can best determine this for you.
In general, desired test results for adults are as
follows: Total cholesterol (TC): Below 200 milligrams of cholesterol per deciliter of blood (mg/dl).
HDL cholesterol: Above 40 mg/dl. LDL cholesterol: Below 130 mg/dlTC/HDL ratio: Below
4.0 Test results outside these desired levels result in a greater risk for heart disease. Your cholesterol level can be too low, as well too high. Low levels of serum cholesterol are associated with malnutrition and hyperthyroidism. If your test results are outside the norm, your doctor will develop a treatment plan that will address the underlying cause of these results. While these usually include making lifestyle changes, some people must take LDL-lowering medication to reduce their risk of heart
disease.
Self-care tips
Most people can control their total serum cholesterol by following a healthy diet; maintaining a healthy weight for their age, height, and body type; and participating in a regular exercise program. A healthy diet includes the daily recommended servings of fruits, vegetables, beans, and whole grains. While you don't need to give up all red meats and foods containing saturated fats, they should be eaten in moderation. The key to a healthy diet is not to deprive yourself of foods you like, but to balance them with more healthy foods.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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