At a Glance
Why Get Tested?
When to Get Tested?
When your doctor 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
A blood sample drawn from a vein in your arm
Test Preparation Needed?
The Test Sample
What is being tested?
This test measures the amount of lipoprotein-associated phospholipase A2 (Lp-PLA2) in the blood. Lp-PLA2 is an enzyme produced by macrophages, immune cells that eat and destroy foreign proteins, old cells, debris, and microorganisms. Most of the Lp-PLA2 in the blood is bound to LDL (low-density lipoprotein, the "bad cholesterol").
Lp-PLA2 appears to play a role in inflammation of blood vessels and is thought to help promote atherosclerosis. Some recent studies have shown that Lp-PLA2 is an independent risk factor for two cardiovascular diseases (CVD), coronary heart disease (CHD), and ischemic stroke. In these studies, increased concentrations of Lp-PLA2 are seen in many people who are 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 American Heart Association. 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, smoking, obesity, high cholesterol levels, increased LDL, and decreased HDL (high-density lipoprotein, the "good cholesterol").
Many people who have one or more risk factors will eventually develop CVD, but a significant number of additional people who have few or no identified risk factors will also develop CVD. This has lead researchers to look for other risk factors that might be either causing CVD or that could be used to determine lifestyle changes and/or treatments that could reduce a person's risk of CVD.
In addition to the traditional risk factors listed above, a low level of chronic, systemic inflammation and inflammation of blood vessels (vascular) is thought to contribute to overall risk for developing CVD. The hs-CRP test is associated with systemic inflammation; high levels are thought to increase CVD risk. The Lp-PLA2 test is associated with vascular inflammation, and high levels are thought to increase the chance of 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.
Ask a Laboratory Scientist
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, 4th Edition: Saunders Elsevier, St. Louis, MO. Pp 682-683.
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Boero, L. et. al. (2009 April 01). Alterations in Biomarkers of Cardiovascular Disease in Active Acromegaly. Medscape Today from Clinical Endocrinology [On-line information]. Available online at http://www.medscape.com/viewarticle/586806 through http://www.medscape.com. Accessed May 2009.
(Updated 2009 May). The Physician's Guide to Laboratory Test Selection and Interpretation, Cardiovascular Disease (Non-traditional Risk Markers) - Risk Markers - CVD (Non-traditional). ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/CardiacDz/CVDRiskMarkerNontrad.html?client_ID=LTD through http://www.arupconsult.com. Accessed May 2009.
(2007 July). Lipoprotein-Associated Phospholipase A2 (PLAC™). ARUP Technical Bulletin [On-line information]. Available online through http://www.aruplab.com . Accessed May 2009.
(Reviewed 2007 November). Lp-PLA2 Test Summary. Quest Diagnostics Interpretive Guide [On-line information]. Available online at http://www.questdiagnostics.com/hcp/intguide/jsp/showintguidepage.jsp?fn=TS_Lp-PLA2.htm through http://www.questdiagnostics.com. Accessed May 2009.
Elkind, M. et. al. (2006 June 14). Genetic and Inflammatory Mechanisms in Stroke. eMedicine [On-line information]. Available online at http://emedicine.medscape.com/article/1163331-overview through http://emedicine.medscape.com. Accessed May 2009.
Lusky, K. (2008 July). New clue for predicting stroke risk: Lp-PLA2. CAP Today [On-line information]. Available online through http://www.cap.org. Accessed May 2009.
Persson, M. et. al. (2007 June). Elevated Lp-PLA2 Levels Add Prognostic Information to the Metabolic Syndrome on Incidence of Cardiovascular Events Among Middle-Aged Nondiabetic Subjects. Arteriosclerosis, Thrombosis, and Vascular Biology. 2007;27:1411 [On-line information]. Available online at http://atvb.ahajournals.org/cgi/content/full/27/6/1411 through http://atvb.ahajournals.org. Accessed May 2009.
What are the Types of Stroke? American Stroke Association [On-line information]. Available online at http://www.strokeassociation.org/presenter.jhtml?identifier=1014 through http://www.strokeassociation.org. Accessed May 2009.