Cholesterol is a fatty substance found in the blood, tissues and organs of the body. It is transported throughout the bloodstream by molecules called lipoproteins, which consist of lipids and proteins. A cholesterol test measures the amount of cholesterol present in the blood. Two types of cholesterol testing are available. A nonfasting cholesterol test that measures total cholesterol only, and a fasting lipid profile that measures total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglycerides.
Types
Your cholesterol test will measure three types of lipids. One is HDL, which carries excess cholesterol from the blood to the liver so it can be removed from the body. HDL is considered "good" cholesterol and lowers the risk of coronary heart disease. LDL carries cholesterol from the liver to the tissues of the body to be deposited in arteries. LDL is known as the "bad" cholesterol and raises the risk of coronary heart disease. Triglycerides are a type of lipid consisting of a molecule of alcohol glycerol attached to three molecules of fatty acids. It is not a form of cholesterol, but it is carried by lipoproteins that also transport cholesterol and therefore contributes to heart disease.
Total Cholesterol Level
Total cholesterol should measure less than 200 mg/dL. A level of 200 to 239 mg/dL is considered borderline high and 240 mg/dL or above is considered high. According to the American Heart Association, a high cholesterol level more than doubles your risk of coronary heart disease as compared to someone with a level less than 200 mg/dL.
HDL Level
An HDL of at least 60 mg/dL is considered ideal and also lowers the risk for coronary heart disease. A level less than 40 mg/dL for men and 50 mg/dL for women is considered low and increases the risk for heart disease.
LDL Level
Your target LDL depends on your risk factor for heart disease. Risk factors include a history of heart attack or stroke, peripheral arterial disease, carotid artery disease, high blood pressure, diabetes, smoking, low HDL, family history of heart disease and males older than 45 or females older than 55. LDL levels should be less than 100 mg/dL for most people. Those at high risk for heart disease should have an LDL of less than 70 mg/dL and those at risk for heart disease should have an LDL of less than 100 mg/dL. 100 to 129 mg/dL is considered above optimal, 130 to 159 mg/dL borderline high, 160 to 189 mg/dL high and 190 mg/dL or above very high. According to the American Heart Association, the average LDL for Americans at least 20 or older is 115 mg/dL.
Triglyceride Level
Triglycerides measuring less than 150 mg/dL are normal, 150 to 199 mg/dL borderline high, 200 to 499 mg/dL high and 500 mg/dL or above very high. Elevated triglycerides are caused by obesity, smoking, excessive consumption of alcohol, physical inactivity and high carbohydrate diets.
Expert Insight
The National Heart, Lung and Blood Institute recommends that adults age 20 and older get their cholesterol checked a minimum of once every five years.
