 LDL & larger particles vs. HDL particles), NMR measured lipoprotein (LDL/HDL) particle ratios even more so, has always had a stronger correlation with myocardial infarction event rates than older methods of measuring lipid transport in the water outside cells.ApoA1 is routinely measured using immunoassays such as ELISA or nephelometry.ApoA1 can be used to create in vitro lipoprotein nanodiscs for cell-free membrane expression systems.