• Also Known As:
  • Platelet-activating Factor Acetylhydrolase
  • PAF-AH
  • PLAC
  • Formal Name:
  • Lipoprotein-associated Phospholipase A2
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At a Glance

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?


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You can order your own FDA approved laboratory testing online or by phone and walk-in to a local lab location with a lab requisition to have your testing services performed. Direct-access laboratory testing provides the same FDA approved tests ordered by your physician from the same CLIA certified laboratories. You pay private-pay prices with a credit card, online checkout is easy. There are no additional fees for lab services or blood work. We do not bill your health insurance company.

You may be able to find your test results on your laboratory’s website or patient portal. However, you are currently at Lab Tests Online. You may have been directed here by your lab’s website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab’s website or portal, or contact your healthcare practitioner in order to obtain your test results.

Lab Tests Online is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.

The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.

If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.

Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called “normal” values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.

While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are “within normal limits.”

For more information, please read the article Reference Ranges and What They Mean.

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 or 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 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. High levels of Lp-PLA2 is also associated with vascular complications in people with diabetes, such as kidney disease.


Common Questions

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 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. However, several studies on drugs that inhibit Lp-PLA2 activity (such as darapladib) found that inhibition had little or no effect on reducing risk of CHD. If future studies found 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 healthcare 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 healthcare 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.

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.

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.

View Sources

Sources Used in Current Review

2018 review performed by Jing Cao, PhD, DABCC, FAACC, Assistant Professor of Pathology and Immunology, Baylor College of Medicine, Associate Director of Clinical Chemistry, Texas Children’s Hospital.

Topbas, C. et. al. (2018 April). Measurement of Lipoprotein-Associated Phospholipase A2 by Use of 3 Different Methods: Exploration of Discordance between ELISA and Activity Assays. Clin Chem 64(4) 697-704. [On-line information]. Available online at http://clinchem.aaccjnls.org/content/64/4/697 through http://clinchem.aaccjnls.org/. Accessed May 2018.

Siddiqui, MK. et. al. (2018 June). Lp-PLA2 activity is associated with increased risk of diabetic retinopathy: a longitudinal disease progression study. Diabetologia 61(6) 1344-1353. [On-line information]. Available online at https://link.springer.com/article/10.1007%2Fs00125-018-4601-7 through https://link.springer.com/journal/125. Accessed May 2018.

O’Donoghue, ML. et. al. (2014 September). Effect of darapladib on major coronary events after an acute coronary syndrome: the SOLID-TIMI 52 randomized clinical trial. JAMA 312 1006–1015. [On-line information]. Available online at https://jamanetwork.com/journals/jama/fullarticle/1900827 through https://jamanetwork.com/journals/jama. Accessed May 2018.

White, HD. et. al. (2014 May). Darapladib for preventing ischemic events in stable coronary heart disease. N Engl J Med 370 1702–1711. [On-line information]. Available online at https://www.nejm.org/doi/full/10.1056/NEJMoa1315878 through https://www.nejm.org/. Accessed May 2018.

Sources Used in Previous Reviews

Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, 4th Edition: Saunders Elsevier, St. Louis, MO. Pp 682-683.

O’Riordan, M. (2008 February 27). Elevated Lp-PLA2 Levels Predict Incident CHD Independent of Traditional Risk Factors. Medscape Today from Heartwire [On-line information]. Available online at http://www.medscape.com/viewarticle/570751. Accessed May 2009.

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. 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. 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. 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. 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. 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. Accessed May 2009.

White H, et. al. Changes in Lipoprotein‐Associated Phospholipase A2 Activity Predict Coronary Events and Partly Account for the Treatment Effect of Pravastatin: Results From the Long‐term Intervention with Pravastatin in Ischemic Disease Study. J Am Heart Assoc. 2013 October; 2(5): e000360. Available online at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3835245/. Accessed December 2013.

O’Riordan, M. (2010 April 29). Modest association between Lp-PLA2 and coronary heart disease. Medscape Multispecialty [On-line information]. Available online at http://www.medscape.com/viewarticle/790614. Accessed March 2014.

(© 1995-2014). Lipoprotein Associated Phospholipase A2 (PLAC). Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/57353. Accessed March 2014.

Sultan, S. and Elkind, M. (Updated 2013 October 31). Genetic and Inflammatory Mechanisms in Stroke. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/1163331-overview#showall. Accessed March 2014.

(2013 November). Lipoprotein-Associated Phospholipase A2: How Effective as a Risk Marker of Cardiovascular Disease and as a Therapeutic Target? BioPortfolio [On-line information]. Available online at http://www.bioportfolio.com/resources/pmarticle/178617/Lipoprotein-Associated-Phospholipase-A2-How-Effective-as-a-Risk-Marker-of-Cardiovascular.html. Accessed November 2013.

Delgado, J. et. al. (Updated 2014 March). Cardiovascular Disease (Non-traditional Risk Markers) – Risk Markers – CVD (Non-traditional). ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/CVDRiskMarkerNontrad.html?client_ID=LTD. Accessed March 2014.

Zalewski, A. et. al. (2006 September). Lp-PLA2: A New Kid on the Block. Clinical Chemistry v 52 (9) 1645-1650. [On-line information]. Available online at http://www.clinchem.org/content/52/9/1645.long. Accessed March 2014.

Pagana, K. D. & Pagana, T. J. (© 2011). Mosby’s Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pg 621.

(©2012) American Association of Clinical Endocrinologists’ Guidelines for Management of Dyslipidemia and Prevention of Atherosclerosis. Available online at https://www.aace.com/files/lipid-guidelines.pdf. Accessed March 2014.

Maiolino G, et al (October 31, 2013). Lipoprotein-Associated Phospholipase A2 Activity Predicts Cardiovascular Events in High Risk Coronary Artery Disease Patients. PLoS One. 2012; 7(10): e48171. Available online at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3485195/. Accessed March 2014.

(April 26 2012) New Clinical Endocrinology Guidelines Support Lp-PLA2 Measurement For Risk Assessment of Coronary Artery Disease. Press Release, Reuters. Available online at http://uk.reuters.com/article/2012/04/26/idUS191175+26-Apr-2012+PRN20120426. Accessed March 2014.


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