Testing
Two common Lp(a) assays disagree on classification for 23% of patients, a study of 144 patients (J Clin Lipidol 2012)
Original title: Lipoprotein(a) particle concentration and lipoprotein(a) cholesterol assays yield discordant classification of patients into four physiologically discrete groups
This study compared Lp(a) cholesterol (measured by Vertical Auto Profile, upper limit of normal 10 mg/dL) and Lp(a) particle concentration (measured by isoform-independent molar assay, upper limit of normal 70 nmol/L) in 144 primary and secondary prevention patients, dividing them into four groups by whether each measure was normal or high. The proportion of patients above the upper limit of normal was similar between the two assays (P=.15), but the two assays discordantly classified 23% of patients, and the four Lp(a)-defined groups differed in their relationships with other lipoproteins: those with elevated Lp(a) cholesterol had higher HDL cholesterol, apolipoprotein A-I, and HDL/apoA-I ratios, while triglycerides were elevated in discordant groups and normal in concordant ones. The findings suggest these four Lp(a)-defined groups are physiologically distinct, warranting further study of which Lp(a) parameter best captures cardiovascular risk.
Original abstract
There is little known about the relative predictive value of different lipoprotein(a) [Lp(a)] assays in clinical use, although each has been shown to predict similar incremental risk over conventional clinical and lipid risk factors. Thus, we examined the classification behavior of two commonly used Lp(a) assays and their associations with other lipid parameters. Serum lipid and Lp(a) concentrations were measured in 144 primary and secondary prevention patients. Lp(a) cholesterol [Lp(a)-C] was measured with the Vertical Auto Profile (upper limit of normal, 10 mg/dL). Lp(a) particle concentrations [Lp(a)-P] were measured with an isoform-independent molar assay (upper limit of normal, 70 nmol/L). The subjects were divided into the following four groups on the basis of their Lp(a)-C and Lp(a)-P levels: normal Lp(a)-P and Lp(a)-C; high Lp(a)-P and normal Lp(a)-C; normal Lp(a)-P and high Lp(a)-C; and high Lp(a)-P and Lp(a)-C. The proportion of subjects with values above the upper limit of normal was similar with both assays (P = .15). However, the Lp(a)-C and Lp(a)-P assays discordantly classified 23% of the study's subjects. In addition, the four Lp(a)-defined groups displayed differences in their relationships with other lipoproteins. The two groups with elevated Lp(a)-C showed significant associations with higher high-density lipoprotein cholesterol, apolipoprotein AI, and high-density lipoprotein cholesterol/apolipoprotein AI ratios. Triglycerides were also noted to be above normal in discordant and normal within concordant Lp(a) groups. Finally, the amount of cholesterol per Lp(a) particle [Lp(a)-C/Lp(a)-P] varied widely across the four groups. These findings suggest that the four Lp(a)-defined groups are physiologically discrete. Further investigation is warranted to assess which parameters among Lp(a)-P, Lp(a)-C, and Lp(a)-C/Lp(a)-P can be used to more accurately characterize Lp(a)-associated cardiovascular risk.
Summary written by lp-a.org from the published abstract; figures as published. Page updated 18 August 2026. Methods.