Lipoprotein (a) Blood Test

A lipoprotein (a) test measures the level of lipoprotein (a) in your blood. A high level of lipoprotein (a) may mean you have a high risk for heart disease and stroke. Lipoproteins are particles made of protein and fats (lipids).

They carry cholesterol through your bloodstream to your cells. The two main groups of lipoproteins are called HDL (high-density lipoprotein) or 'good' cholesterol and LDL (low-density lipoprotein) or 'bad' cholesterol. Lipoprotein (a) is a type of LDL.

These lipoproteins carry cholesterol to your cells through your arteries (blood vessels that carry oxygen-rich blood from your heart and lungs to your body). If you have high levels of LDL particles, cholesterol can build up in your arteries and form blockages called plaques. This condition is known as atherosclerosis, or 'hardening of the arteries,' which means that the arteries thicken and become less flexible.

It can lead to many serious medical conditions including: Coronary artery disease, narrow or blocked arteries in your heart; Heart attack; Stroke; Peripheral arterial disease, blocked arteries in your legs or arms; Other blood vessel diseases; Lipoprotein (a) particles are stickier than other types of LDL particles, so they may be more likely to cause blockages and blood clots in your arteries. As a result, high levels of lipoprotein (a) may mean you have a high risk for heart disease, stroke, and other serious conditions related to blockages and blood clots in your arteries. A lipoprotein (a) blood test can give you a more accurate understanding of your risk than a routine cholesterol test that only measures your total LDL cholesterol level.

That's because a routine cholesterol test may show that your LDL cholesterol level is 'healthy,' but if a large percentage of your LDL cholesterol is carried by lipoprotein (a) particles, your risk for heart disease and stroke could still be high.

Why this test is done

Your provider may order the test if you have certain signs or health conditions that mean you have a high risk for blockages in your arteries, such as:

• A family health history of early heart or blood vessel disease (before age 55 for a father or brother and before age 65 for a mother or sister)
• High LDL cholesterol, even though you take medicine to lower it
• Heart or blood vessel disease, especially if your cholesterol and triglyceride (another type of fat in your body) levels are normal without taking medicine to lower them
• Signs of familial hypercholesterolemia, an inherited (passed down through families) condition that causes high cholesterol levels
• Had more than one heart attack or more than one angioplasty, a procedure to open up narrow or blocked arteries in your heart

The test may also be used to help make decisions about the risks and benefits of taking cholesterol medicine to lower your chance of developing heart and blood vessel disease.

How to prepare

Preparations for a lipoprotein (a) test depend on the lab doing the test. Usually, you need to fast (not eat or drink) for 9 to 12 hours before your blood is drawn. Your provider will let you know if there are any special instructions to follow.

Certain substances can affect your test results. Before you get a lipoprotein (a) test, tell your provider if you have been drinking alcohol or taking niacin supplements, aspirin, or oral estrogen hormones.

Sample type

Blood

Other names for this test

cholesterol Lp(a), Lp(a)