This blood test checks the levels of cholesterol in your body. A lipid panel will show the levels of your total cholesterol, your LDL ("bad") cholesterol, and your HDL ("good") cholesterol. In general, the higher your total and LDL cholesterol levels, the higher your risk for coronary heart disease. But some heart attacks happen in people who don't have a high LDL level.
Some researchers believe that measuring your non-HDL cholesterol levels gives a better assessment of the risk for heart disease than measuring only LDL. This is especially true if you have high triglycerides. Your non-HDL cholesterol level is found by subtracting your HDL cholesterol from your total cholesterol.
High cholesterol is one of the accurate predictors of heart disease, so it's important to know your numbers. When your LDL cholesterol level is high and HDL cholesterol is low, you may be at risk for a heart attack or stroke.
Here's a breakdown of LDL cholesterol levels and health:
Less than 70 milligrams per deciliter (mg/dL) – this is your goal if you're at very high risk for a heart attack
Less than 100 mg/dL – the goal for people with heart disease or diabetes
100 to 129 mg/dL – near or above the ideal level
130 to 159 mg/dL – borderline high
160 to 189 mg/dL – high
190 mg/dL and above – very high
Here's a breakdown of total cholesterol levels and health:
Less than 200 mg/dL – you are at low risk for heart disease
200 to 240 mg/dL – borderline high
240 mg/dL and above – high
Ideally, HDL cholesterol should be above 40 mg/dL for men and above 50 mg/dL for women. The higher your HDL level, the better.
The test for non-HDL cholesterol isn't usually part of screening for your total cholesterol. But if you have high blood pressure, diabetes, or other risks for heart disease, your chances of having a heart attack are higher than normal. In these cases, your provider may calculate your non-HDL cholesterol, too.
Your provider may also order this test if a blood test shows you have high levels of triglycerides, another type of fat in the blood. A high non-HDL cholesterol level alone isn't a warning sign that something is wrong with your arteries or heart, but if your triglycerides measure more than 200 mg/dL, your provider may prescribe medicine to help lower both your LDL and your non-HDL cholesterol.
If your provider suspects you have heart disease, you may also get these tests:
Electrocardiogram (EKG). This tests your heart's electrical impulses to see if your heart is beating normally.
Stress test. This test is done while you have an EKG. You may have to walk or run on a treadmill.
Echocardiogram. This is a picture of your heart made from sound waves.
Cardiac catheterization. A tube is put into your blood vessel and dye is injected. Clogs will then show up on an X-ray.
People with a history of artery disease, stroke, kidney disease, or diabetes are also at higher risk for heart disease, so tests may be done to look for these problems, too.
Although no clear standards exist for non-HDL levels, most medical experts believe that lowering LDL and non-HDL cholesterol at the same time will cut your heart disease risk.
According to federal cholesterol program guidelines, your non-HDL cholesterol level goal should be 30 mg/dL higher than your LDL cholesterol level goal. For example, if you are aiming for an LDL cholesterol of 100 mg/dL, then your goal for non-HDL should be 130 mg/dL.
If you have diabetes, smoke, have a family history of heart disease, or have other risk factors, your cholesterol levels may need to be much lower. Talk with your doctor about where your cholesterol levels should be.
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.
What you eat, how often you exercise, and whether you smoke can affect your cholesterol levels. So can certain medicines.
A lipid test can be done with or without fasting. But if your triglycerides are going to be measured, you may need to fast, meaning you can have nothing but water for 12 to 14 hours before the test.