Cholesterol is a waxy substance that allows your body to synthesize various hormones and vitamins. While cholesterol plays important roles in your body, too much cholesterol can increase your risk of heart disease and stroke. A cholesterol screening, which indicates the amount of cholesterol in your blood, can measure your cholesterol ratios and help you determine if you are within desirable ranges.
Physiology
Cholesterol belongs to the class of nutrients called lipids. Lipids are hydrophobic, which means that they do not dissolve in water. Because blood is composed mostly of water and cholesterol is hydrophobic, cholesterol cannot dissolve in the blood. As a result, cholesterol circulates throughout the bloodstream in its solid form.
Substances called lipoproteins carry cholesterol throughout your body. Lipoproteins are made mostly of protein. The lipoprotein and cholesterol package contains protein on the outside and fat on the inside. There are different types of lipoprotein and cholesterol packages, each with a different ratio of protein and fat.
LDL Cholesterol
LDL, or low-density lipoprotein, cholesterol is often referred to as bad cholesterol. LDL cholesterol contributes to the accumulation of plaque on the walls of the arteries, a medical condition called atherosclerosis. The higher the amount of LDL cholesterol in your blood, the higher your risk of heart disease.
LDL cholesterol levels less than 100 mg/dL are considered optimal, while LDL levels from 100 to 129 mg/dL. If your LDL cholesterol levels accumulate to 130 to 159 mg/dL, they are considered borderline high. LDL levels from 160 to 189 mg/dL are high and levels over 190 mg/dL are very high. The goal for LDL cholesterol is to get your numbers as low as possible.
HDL Cholesterol
HDL, or high-density lipoprotein, is the type of cholesterol often referred to as good cholesterol. High-density lipoproteins carry cholesterol in the bloodstream to the liver so that it can be removed from your body. HDL actually decreases your cholesterol levels.
If your HDL levels are below 40 mg/dL, you are considered at a major risk for heart disease. HDL levels of 60 mg/dL and higher are considered protective against heart disease. The goal for HDL cholesterol is to get your numbers as high as possible.
Total Cholesterol
Your total cholesterol includes the total of LDL cholesterol, HDL cholesterol and other fatty substances in your blood. High total cholesterol increases your risk for heart disease.
Total cholesterol levels less than 200 mg/dL are considered desirable. Levels between 200 and 239 mg/dL are defined as borderline high and levels 240 mg/dL and higher are considered very high.
