What is the vertical cholesterol profile test and what's its best use case?

Limited: Not sure what you mean by "vertical", but if you mean the extended lipid profiles with particle size and density, i would say practical use is limited. In my research work, extensive lipid profiles important, but clinically, very limited data suggesting that knowledge of the extra data actually changes treatment and outcomes. Question usually is to whether to add niacin; other ways to decide.

Particle size: Hello, the main difference between a "regular" cholesterol test and VAP is the VAP gives particle size. It is thought that smaller more dense LDL is more atherogenic - will cause atherosclerosis more readily than larger more buoyant LDL. Even better are tests that give particle concentration, such as LDL-P. Atherosclerosis is concentration driven so the more particles of LDL the worse it is.