The PLAC test measures the amount of lipoprotein associated phospholipase (Lp-PLA2) in blood. Lp-PLA2 is an enzyme primarily associated with low density lipoprotein (LDL). LDL carries Lp-PLA2 to the coronary artery walls where it activates an inflammatory response. This makes plaque, if present, more prone to rupture. Because this enzyme is associated with causing inflammation of coronary artery walls, high levels of Lp-PLA2 would therefore seem to indicate an increased risk of heart attack or stroke. Traditional inflammatory markers, such as hsCRP, and CRP, whilst recognised as being useful systemic inflammatory markers are not as sensitive for identifying inflammation of the coronary artery walls. As a result, the PLAC Test, which is measuring levels of Lp-PLA2, serves as a specific independent coronary marker.