Cholesterol test

Definition

A total cholesterol test measures all the cholesterol in your blood.

Cholesterol is a soft, wax-like substance found in all parts of the body. Your body needs a little bit of cholesterol to work properly. But too much cholesterol can clog your arteries and lead to heart disease.

Some cholesterol is considered "good" and some is considered "bad." Different blood tests are needed to individually measure each type of cholesterol.

See also:

• HDL test (high density lipoprotein, or "good" cholesterol)
• High blood cholesterol and triglycerides
• LDL test (low density lipoprotein, or "bad" cholesterol)
• Lipid profile

Alternative Names

Total cholesterol test

How the test is performed

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

How to prepare for the test

To get the most accurate results, you should not eat or drink anything for 9 - 12 hours before the test. You may drink water, but avoid other beverages, such as coffee, tea, or soda. For the purpose of screening, the total cholesterol is often done without fasting overnight.

Your health care provider may tell you to stop taking drugs that can affect the test. Never stop taking any medicine without first talking to your doctor.

How the test will feel

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed

A coronary risk profile may be done:

• To screen adults and children for high blood cholesterol
• To follow people who have had high cholesterol levels and are being treated

Screening for adults:

• The first screening test is performed between ages 20 - 35 in men, and ages 20 - 45 in women (Note: Different national medical organizations recommend different starting ages.)
• Follow-up screening should be done every 5 years.
• Screening is done for anyone who develops diabetes, high blood pressure, heart disease, or another illness caused by atherosclerosis.
• Follow-up testing is done to determine how well diet and medications are controlling high cholesterol.

This test is often done to determine your risk for coronary artery disease. High blood cholesterol and triglycerides have been linked to heart attack and stroke.

The total cholesterol test may be done as part of a lipid profile, which also checks for LDL, HDL, and triglycerides.

The test may also be done for:

• Arteriosclerosis of the extremities
• Familial dysbetalipoproteinemia
• Familial hypercholesterolemia
• Hypothyroidism
• Kidney disease
• Liver disease
• Type 1 or type 2 diabetes
• Primary biliary cirrhosis

Normal Values

Total cholesterol is an important measure of both bad and good cholesterol. Other lab tests are done to measure specific amounts of good (HDL) and bad (LDL) cholesterol. A cholesterol breakdown including LDL and HDL is preferred under certain circumstances.

The total cholesterol values listed below are used to target therapy:

• Desirable: Under 200 milligrams per deciliter (mg/dL)
• Borderline high: 200 to 239 mg/dL
• High risk: 240 mg/dL and higher

What abnormal results mean

In general, a total cholesterol value over 200 mg/dL may mean you have a greater risk for heart disease. However, LDL levels are a better predictor of heart disease, and they determine how your high cholesterol should be treated.

High total cholesterol levels may be caused by:

• Biliary cirrhosis
• Familial hyperlipidemias
• High-fat diet
• Hypothyroidism
• Nephrotic syndrome
• Uncontrolled diabetes

Low cholesterol levels may be caused by:

• Hyperthyroidism
• Liver disease
• Malabsorption (inadequate absorption of nutrients from the intestinal tract)
• Malnutrition
• Pernicious anemia
• Sepsis

What the risks are

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks, although rare, may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Special considerations

Any acute illness can raise or lower your total cholesterol number. If you have had an acute illness in the 3 months before having this test, you should have this test repeated in 2 or 3 months. Even a flare-up of arthritis can affect your cholesterol level.

Other conditions associated with high cholesterol include:

• Pregnancy
• Removal of the ovaries

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References

Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Executive summary of the third report of the National Cholesterol Education Program (NCEP) expert panel on detection, evaluation, and treatment of high blood cholesterol in adults (Adult Treatment Panel III). JAMA. 2001;285:2486-2497. Updated 2004.

Semenkovich CF. Disorders of lipid metabolism. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 217.

U. S. Preventive Services Task Force. Screening for lipid disorders in adults: U.S. Preventive Services Task Force recommendation statement. Rockville (MD): Agency for Healthcare Research and Quality (AHRQ); 2008 Jun.