Low-density lipoprotein-cholesterol, LDL-C
This test measures the amount of low-density lipoprotein-cholesterol (LDL-C) in your blood.
LDL cholesterol is often called "bad" cholesterol because it causes plaque to build up inside your arteries and leads to heart disease.
Cholesterol screening is recommended for men older than 35 and women older than 45. If you have risk factors for heart disease, such as a family history of heart disease, you may need to begin regular testing of cholesterol as young as age 20. LDL cholesterol is one of a group of lipoproteins that can indicate heart disease, so this test is used to help diagnose it.
Lowering LDL-C levels can help prevent heart disease.
You may have this test as part of a routine exam to check for high cholesterol.
You may also have this test if you already have heart disease caused by high cholesterol. The test can help your doctor find out how well your treatment is working.
Your doctor may also order other blood tests to measure the levels of various fats in your blood, including:
High-density lipoprotein, or HDL
Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.
Results are given in milligrams per deciliter (mg/dL). The normal range of LDL-C is 50 to 130 mg/dL. A level below 70 mg/dL is considered best for people who have diabetes or heart disease risk factors. In general:
100 to 129 mg/dL is near or just above optimal
130 to 159 mg/dL is borderline high
160 to 189 mg/dL is high
190 mg/dL and over is very high
It's possible to have extremely low levels of LDL-C, but this is rare. This condition is usually a sign of a problem processing vitamins A, D, E, and K.
If your levels of LDL-C are high, the condition is called dyslipidemia. High levels may mean that you have an imbalance in your diet, but the condition is often hereditary. Changing your lifestyle habits and taking medications to reduce LDL levels may help you reduce the risk for heart disease and manage the condition if you already have it.
The test requires a blood sample, which is drawn through a needle from a vein in your arm.
Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.
Smoking cigarettes can increase LDL-C levels. Stress, certain minor ailments, and some drugs can also affect your results.
You may need to not eat or drink anything but water for a certain time before having the test. In addition, be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.