PLAC refers to the circulating form of lipoprotein-associated phospholipase A2 (Lp-PLA2), an enzyme in the phospholipase A2 family. Biochemically, it hydrolyzes oxidized phospholipids on lipoproteins and is commonly bound to LDL and, to a lesser extent, HDL. Cells in the artery wall and inflammatory cells release the enzyme, which then associates with circulating lipoproteins. Clinically, Lp-PLA2 was characterized in the late 20th century and has been studied as a marker of vascular inflammation and oxidized-lipid activity. Laboratory assays report either mass or enzymatic activity. Its core biological role is processing oxidized phospholipids into products such as lysophosphatidylcholine and oxidized free fatty acids, which can influence endothelial cells and local inflammatory signaling.

Elevated PLAC levels may indicate greater lipoprotein-associated inflammatory activity and increased oxidized-lipid processing at the vascular interface. In practice, higher values are interpreted as a pattern consistent with active vascular inflammatory signaling and lipid oxidation, especially when seen alongside abnormal lipids or other inflammation markers. Low PLAC levels may reflect lower lipoprotein-associated enzyme activity, less oxidized-lipid burden, or differences in lipoprotein carriers and assay variability. Any single PLAC result is most informative when interpreted with the full Cardio Zoomer profile—lipids, inflammatory markers, oxidative stress measures, and clinical context.

Cardio Zoomer includes PLAC to add a targeted measure of lipoprotein-linked vascular inflammation and oxidized-lipid activity. It complements lipid particle measures, hs-CRP, and redox markers to help clinicians distinguish inflammatory or oxidation-driven patterns from other lipid-related findings, supporting more precise interpretation of a patient’s cardiovascular biology.