LDL-P (LDL particle number)

LDL-P (LDL particle number) counts how many LDL particles are in your blood, rather than how much cholesterol they carry. It is usually measured by NMR spectroscopy or ion-mobility analysis. Here is why the count matters: each LDL particle carries exactly one apolipoprotein B-100. So LDL-P closely matches the apoB particle count, both measuring the burden of artery-clogging particles. (The units differ: LDL-P in nmol/L versus apoB in mg/dL, and apoB also counts VLDL, IDL, and Lp(a).) Sometimes your LDL-cholesterol and your LDL-P disagree, most often with high triglycerides, insulin resistance, or low HDL. In those 'discordance' cases, LDL-P is consistently the better predictor of heart events. That supports the idea that it is the number of particles, not the cholesterol packed in each one, that drives artery disease. Levels are reported in nmol/L, with higher risk above roughly 1,000 to 1,200 nmol/L.

Last reviewed: June 22, 2026

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