Patient Test Information

Lp-PLA_sub_2__sub_

Also known as:

LpPLA2; Lp-PLA2 Activity Test; Platelet-activating Factor Acetylhydrolase; PAF-AH; PLAC

Formal name:

Lipoprotein-associated Phospholipase A2

Related tests:

Lipid Profile; Lipoprotein Subfractions; Cardiac Risk Assessment; hs-CRP; Cholesterol; LDL Cholesterol; HDL Cholesterol

Why Get Tested?

To help determine your risk of developing cardiovascular disease (CVD), including your risk of coronary heart disease (CHD), and ischemic stroke

When to Get Tested?

When your healthcare provider determines that you are at a moderate to high risk of developing CVD or of having an ischemic stroke; when you have a family history of CVD or CHD

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

None

How is it used?

The Lp-PLA2 test is sometimes used to help evaluate a person's risk of developing coronary heart disease (CHD) or to help determine the risk of having an ischemic stroke.

Lp-PLA2 is an enzyme that appears to play a role in the inflammation of blood vessels and is thought to help promote atherosclerosis. Some recent studies have shown that Lp-PLA2 is an independent risk marker for cardiovascular disease (CVD), including coronary heart disease (CHD), and ischemic stroke.

The test would typically be used to evaluate an individual who is at a moderate to elevated risk for CHD or stroke, someone with one or more other risk factors. For instance, it may be ordered when someone has normal or minimally elevated lipid levels, borderline high blood pressure (hypertension), or metabolic syndrome.

An Lp-PLA2 test may sometimes be used along with an hs-CRP test to evaluate a person's level of underlying inflammation associated with CVD risk. However, unlike hs-CRP, the Lp-PLA2 test is not affected by conditions other than CVD that can cause general inflammation, so it may be used when someone has an inflammatory condition, such as arthritis.

Lp-PLA2 is a relatively new test that is not frequently ordered and its full clinical usefulness has yet to be established. It is intended to give additional information, not to replace cholesterol and other lipid level testing.

Some researchers are exploring whether treatment to lower Lp-PLA2 levels will lower a person's risk of CHD and ischemic stroke. If the risk of CVD and stroke is decreased when Lp-PLA2 is lowered, then the Lp-PLA2 test may be ordered more frequently and be used to monitor a person's response to treatment.

When is it ordered?

Lp-PLA2 is a relatively new test that is not frequently ordered. Some health practitioners may order it along with other cardiac risk markers when someone has a family history of CHD, has metabolic syndrome, and/or is considered to be at a moderate to elevated risk for CHD or ischemic stroke.

What does the test result mean?

A significantly elevated Lp-PLA2 level indicates an increased risk for developing CHD or of having an ischemic stroke and provide a health practitioner with additional information about the tested person's overall risk.

A low or normal Lp-PLA2 means that this factor does not contribute to the tested person's risk of CVD.

The test is not diagnostic of CHD or ischemic stroke; it is a risk indicator. Many people with increased concentrations will not develop these conditions, and some with normal levels will.

Is there anything else I should know?

While the findings from recent studies support the potential usefulness of Lp-PLA2 in CHD  and ischemic stroke risk assessment, its ultimate clinical utility has yet to be established.

The Lp-PLA2 test is not widely available. In most cases, the blood sample will be sent to a reference laboratory and results will be available within a few days.

What is being tested?

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an enzyme that appears to play a role in the inflammation of blood vessels and is thought to help promote atherosclerosis. This test measures the amount and activity of Lp-PLA2 in the blood.

Some recent studies have shown that Lp-PLA2 is an independent risk marker for cardiovascular disease (CVD), including coronary heart disease (CHD), and ischemic stroke. In these studies, increased concentrations of Lp-PLA2 were seen in many people who were diagnosed with CHD and ischemic stroke, regardless of other risk factors. These findings make this relatively new test potentially useful as one of a growing number of cardiac risk markers that are used to help determine a person's risk of developing CVD.

CVD causes more deaths in the U.S. each year than any other cause, according to the Centers for Disease Control and Prevention. CHD and ischemic stroke are both associated with the buildup of unstable fatty plaque deposits in the arteries that can lead to blockages in blood vessels and to heart attacks or brain damage. There are a variety of risk factors that have been identified as being associated with both conditions, including high blood pressure, diabetes, metabolic syndrome, smoking, obesity, high cholesterol levels, increased LDL (low-density lipoprotein, the "bad cholesterol"), and decreased HDL (high-density lipoprotein, the "good cholesterol").

Many people who have one or more of the commonly recognized risk factors will eventually develop CVD, but a significant number of people who have few or none of these risk factors will also develop CVD. This has lead researchers to look for additional markers that might identify those at increased risk of CVD.

In addition to the traditional risk factors listed above, a low level of chronic, systemic inflammation and blood vessel (vascular) inflammation are thought to contribute to overall risk for developing CVD. The hs-CRP test is associated with systemic inflammation; high levels are associated with increased CVD risk. The Lp-PLA2 test is associated with vascular inflammation, and high levels are thought to increase the chance of cardiovascular events, including heart attack or stroke.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

  1. How deadly are strokes?

    According to the American Stroke Association, stroke is the fourth leading cause of death in the United States and a leading cause of disability. More than 80% of strokes are ischemic.

  2. Should everyone have an Lp-PLA2 test? 

    It is not currently indicated or recommended by major health organizations as a screen for the general population or recommended yet as a primary cardiac risk marker. Your healthcare provider can help you determine the best tests to determine your risk of developing CVD and provide you with information about changes you can make to lower your risk.