α-4 HDL Test

High-density lipoprotein, or HDL, is not a single particle but a family of particles of different sizes and compositions, each with distinct roles in the body. The α-4 HDL subpopulation is one of the smaller members of this family. Its defining features include a relatively simple protein makeup, fewer apolipoproteins (the structural proteins that hold HDL together), and an enrichment in sphingomyelin, a type of lipid that helps stabilize cell membranes. Compared to larger HDL particles, α-4 HDL carries fewer proteins involved in inflammation control and antioxidant activity.