About PLAC®: The PLAC test is a blood test that measures the level of Lp-PLA2, an enzyme highly specific for vascular inflammation and implicated in the formation of rupture-prone plaque. The PLAC test is cleared by the FDA to aid in assessing risk of both coronary heart disease and ischemic stroke associated with atherosclerosis.
Clinical Significance: Lipoprotein-associated Phospholipase A2 (Lp-PLA2) is produced within the plaque itself. Because elevations in Lp-PLA2 are independent from traditional cardiovascular risk factors, including obesity, the results of the PLAC test provides valuable additive information to help determine appropriate patient care.
Results from the Atherosclerosis Risk in Communities (ARIC) study indicated that individuals with elevated levels of Lp-PLA2 had a twofold increased risk of suffering an ischemic stroke over a period of 6-8 years compared to individuals with low levels of Lp-PLA2. Patients with elevated levels of Lp-PLA2 and high blood pressure were six-fold more at risk for ischemic stroke.
Appropriate Use of the Test: The test helps identify patients who have "hidden" cardiovascular risk due to the formation of rupture-prone plaque. Suitable patients may include those with two or more risk factors, such as metabolic syndrome or hypertension, even if their overall lipid profiles appear normal.
The PLAC test may be used as a management tool in patients with borderline to high risk for coronary heart disease or ischemic stroke events. It is not recommended for screening low risk patients.
Methodology: The diaDexus PLAC test is a high complexity, enzyme linked immunosorbent assay using two specific monoclonal antibodies for the quantitative determination of Lp-PLA2 in human serum. This test is now performed at MuirLab / John Muir Health Lab Service.
Specimen: Collection: Submit one 5 mL gold-top SST. Transport: Routine courier pickup. Storage: Store at 2-8°C for up to 7 days.