Cholesterol is a major component to your health. High blood cholesterol can be a major contributor to heart disease and stroke, which is why you should have your cholesterol levels checked during your annual physical. Cholesterol screenings measure your level of low-density lipoprotein (LDL), high-density lipoprotein cholesterol (HDL), and triglycerides. A small sample of blood will be drawn to get an accurate reading during your screening. All samples are generally taken at the same time and analyzed in a laboratory to give you accurate results. Avoiding food consumption, beverages and often medications, also known as fasting, is common for cholesterol screening preparation. Your physician will tell you if you should fast in advance (generally nine to 12 hours prior to your appointment). If you do not fast when the blood sample is drawn, only the values for total cholesterol and HDL cholesterol will be usable. This is often the case because the amount of LDL and triglycerides can be affected by what you have recently consumed. When you screening is complete, your physician will interpret your cholesterol numbers based on your age, family history and other factors such as high blood pressure or whether you are or were a smoker. If you are over the age of 20 years, you should have your cholesterol checked every four to six years. If your risk factors are higher, you may need to have your cholesterol checked more often. Talk to your doctor about your cholesterol and how often you should have it checked.