Cholesterol

Diagnosis

A blood test for cholesterol should include the entire lipoprotein profile: LDL, total cholesterol, HDL, and triglycerides. It is very difficult to measure LDL levels by themselves, but LDL levels can be reliably calculated using total cholesterol and HDL levels.

To obtain a reliable cholesterol reading, experts advise:

• Avoid strenuous exercise for 24 hours before the test.
• Do not eat or drink anything but water for 12 hours beforehand.
• If the test results are abnormal, a second test should be performed between 1 week and 2 months after the first test.

Home Tests. Tests are available for home use and in public locations, such as shopping malls and pharmacies. For example, the CholesTrak Test can be taken at home with results in 10 minutes, but it measures only total cholesterol. The BioSafe Cholesterol Panel Test is also a home test, but it needs to be sent to a laboratory. This test, however, is very accurate and provides a full lipid profile.

Tests for Markers of Heart Disease in People with Unhealthy Lipid Levels

Certain blood tests for factors associated with inflammation in the arteries indicate a higher risk for heart disease, even in people without unhealthy lipids:

• C-reactive protein (CRP). CRP is regulated by a very potent immune factor called interleukin-6. Elevated levels have been strongly associated with the inflammatory response and a higher risk for heart attack, even in people with normal cholesterol levels. CRP is also associated with high blood pressure, insulin resistance (the primary problem in type 2 diabetes), and obesity.
• A high white blood cell count.
• Elevated fibrinogen (a factor responsible for blood clotting).
• Lipoprotein-associated phospholipase A2 may prove to be another marker for inflammation and heart disease. Studies suggest that it may play some causal role in coronary artery disease.

Skin Test

A new type of test measures cholesterol levels in the skin. High skin levels may indicate an increased risk for atherosclerosis and serious heart disease.

Screening Guidelines General Screening Recommendations. Experts groups differ slightly on when screening should start, but the following are generally accepted recommendations: Periodic cholesterol testing in all adults starting at age 20. Adults with normal cholesterol levels do not need to have the test repeated for 5 years unless changes occur in lifestyle (including weight gain and diet). Adults with risk factors for heart disease or stroke should be rechecked every 2 years. Selective screening of children who are at risk for high cholesterol and heart disease or familial hypercholesterolemia, which is genetically elevated cholesterol. Risk factors include having parents with total cholesterol levels greater than 240, or having a parent or grandparent who had symptomatic heart disease at age 55 or younger. Patients already being treated for high cholesterol should be checked every 2 - 6 months.

Highlights
Introduction
Cholesterol's Effect on the Heart
Cholesterol's Effect on the Brain
Risk Factors
Symptoms
Diagnosis
Lifestyle Changes
Treatment
Resources
References

Review Date: 7/23/2007
Reviewed By: Alan Greene, MD, FAAP, Chief Medical Officer, A.D.A.M., Inc.; and Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.

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