Table 1.

An overview of methods used to isolate high-density lipoprotein subspecies. HDL: high-density lipoprotein

METHOD	SUBSPECIES	ADVANTAGES	DISADVANTAGES
Ultracentrifugation	HDL 1,2,3 HDL 2b,2a, 3A,3b, and 3c	Size and density separation	Overlap with density similar lipoproteins like Lp (a) Imparts ionic strength and sheer stress and uses high salt concentrations
Two-dimensional gel electrophoresis	Charge: pre-beta, alpha, and pre-alpha Size: pre-beta-1 HDL, pre-beta-2, alpha 4- HDL, alpha 3- HDL, alpha-2 HDL, alpha-1 HDL, pre-alpha	Charge and size separation	Particles are not recoverable from the gel for functional analyses
Nuclear magnetic resonance spectroscopy	Small, medium, large. Newer algorithms can detect seven subclasses of HDL	Size separation High throughput Can quantify a particle number and particle size	Assumes that a constant number of methyl groups on each HDL subclass is constant, although newer algorithms account for variation Potential interference from plasma proteins Collinearity among subclasses needs to be accounted for in the analysis
Ion mobility	Very large, large, medium, small, and very small subspecies	Size separation Can quantify a particle number	HDL is isolated by ultracentrifugation first
Gel filtration	Six HDL subclasses and four lipid poor subspecies	Size separation Ability to isolate low abundant HDL particles Recoverability of HDL subclasses to study function	Time intensive Coelution with other plasma proteins such as albumin and globulins