Cholesterol is a fat-like substance found in all cells of the body. It is produced by the body, and also found in many foods. There are two types of cholesterol. The first is LDL cholesterol and is considered the "bad" cholesterol. The second is HDL cholesterol and is considered the "good" cholesterol. A typical blood test for cholesterol, also called a lipoprotein profile, will measure total cholesterol, HDL cholesterol, LDL cholesterol and triglycerides.
Testing
People are concerned about monitoring their cholesterol level because high levels of cholesterol are associated with an increased risk of heart disease and stroke. MayoClinic.com recommends that all adults older than 20 should have a lipoprotein profile every five years. Getting a cholesterol test is particularly important for people with existing risk factors for heart disease. As outlined by the National Cholesterol Education Panel, these risk factors include high blood pressure, diabetes, cigarette smoking, physical inactivity, obesity and a family history of heart disease.
LDL Cholesterol Levels
LDL cholesterol is also known as "bad" cholesterol because it can build up in the arteries of the body and cause a blockage. If this happens in the heart or brain, a heart attack or stroke can occur. A lower level of LDL cholesterol is associated with a lower risk for heart attack and stroke, according to the American Heart Association. With LDL cholesterol, lower is better. According to the American Heart Association, an LDL cholesterol level of less than 100 mg/dL is optimal, while LDL levels between 100 and 129 mg/dL are near-optimal. Levels between 130 and 159 mg/dL are borderline high, and levels between 160 and 189 mg/dL are high. Any HDL level above 190 mg/dL is considered very high.
HDL Cholesterol Levels
HDL cholesterol is also known as the "good" cholesterol because it carries cholesterol to the liver for disposal. High levels of HDL seem to protect against heart disease, according to the American Heart Association, so for HDL cholesterol, higher is better. The American Heart Association states that HDL cholesterol levels of 60 mg/dL or higher are best. Conversely, levels of HDL that are less than 40 mg/dL for men or 50 mg/dL for women are too low and present a major risk factor for heart disease.
Total Cholesterol Levels
Total blood cholesterol is a measure of LDL cholesterol, HDL cholesterol and lipid components of blood known as triglycerides. According to the American Heart Association, the ideal total cholesterol level is less than 200 mg/dL. A total cholesterol of 200 to 239 mg/dL is considered borderline high, while a cholesterol level of 240 mg/dL and above is high. Caution should be taken, however, when using total cholesterol alone as an indicator for heart disease risk. Since total cholesterol is a combination of both LDL and HDL, it is possible to have a high total cholesterol but a very low LDL and a very high HDL. It is always important to look at all components of the lipoprotein profile when evaluating a person's cholesterol.
Normal Cholesterol Ratios
Another potentially useful way to interpret cholesterol results is to look at the ratio of total cholesterol to good cholesterol, or the cholesterol/HDL ratio. In this formula, as total cholesterol decreases and HDL increases, this ratio gets smaller. The smaller the ratio, the better. According to MayoClinic.com, a ratio of 4-to-1 or lower is considered protective against heart disease, while a higher ratio indicates a higher risk for heart disease.
References
- MayoClinic.com: "Cholesterol Test: Why It's Done"
- National Cholesterol Education Program: "Detection, Evaluation and Treatment of High Blood Cholesterol in Adults"
- American Heart Association: "What Your Cholesterol Levels Mean"
- Harvard Health Publications, Harvard Medical School: "Which Cholesterol Test Should You Get?"
- MayoClinic.com: "How Important is Cholesterol Ratio?"
