A cholesterol test is a blood test that measures the amounts of the different types of cholesterol and triglycerides in your blood. This test is commonly used as a part of a routine physical examination to assess your risk for heart disease.
A cholesterol test measures the amount of:
- total cholesterol: the amount of all types of cholesterol found in the blood
- high-density lipoprotein (HDL) cholesterol: also known as "good" cholesterol because it helps reduce LDL cholesterol
- low-density lipoprotein (LDL) cholesterol: also known as "bad" cholesterol because it can cause the buildup of plaques that narrow arteries and increase the risk of heart attack and stroke
- triglycerides: food energy that is not used is converted into this type of fat
Your doctor will determine how often you should have this test. For most people, it is recommended that you have a cholesterol test at the age of 20. It is especially important that you check your cholesterol regularly if you have any of the following risk factors for high cholesterol and heart disease:
- you are male and over 40 years of age
- you are female and over 50 years or age or are postmenopausal
- you have diabetes
- you have a family history of high cholesterol or heart disease
- you are overweight
A patient having blood collected for a cholesterol test.
Risks and precautions
Cholesterol test is usually a straightforward and safe procedure. However, there are some risks of complications or side effects, including:
- excessive bleeding
- fainting or feeling lightheaded
- blood accumulating under the skin
- swollen vein
Before the test
Your doctor may ask you to not eat or drink anything for 9 to 12 hours before to increase the reliability of the test. You can drink water but beverages such as coffee, tea, or soda should be avoided. In addition, you should avoid eating high-fat foods, drinking alcohol, or exercising intensely before the test.
If you are taking any prescription or over-the-counter (non-prescription) medications, supplements, or herbal products, make sure you inform your doctor or pharmacist. Ask them whether it is necessary for you to stop taking any of these medications and products before the test. It is also important to tell them if you have allergies to certain medications or have certain medical conditions.