LDL Particle Number
The number of LDL particles in the blood, measured by NMR spectroscopy or ion mobility.
| Typical reference range | below 1,138 nmol/L |
| Commonly cited optimal range | below 1,000 nmol/L |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Each LDL particle carries a variable amount of cholesterol, so two people with the same LDL-C can have very different particle counts. LDL-P directly counts particles using nuclear magnetic resonance (Labcorp NMR LipoProfile) or ion mobility (Quest Cardio IQ).
Why it matters
The number of particles, rather than the cholesterol they carry, drives how many enter the artery wall. When LDL-P and LDL-C disagree (discordance), LDL-P and ApoB track cardiovascular risk more closely; discordance is common in insulin resistance and diabetes.
What a high result can mean
High LDL-P with normal LDL-C typically indicates many small, cholesterol-depleted particles, a pattern associated with insulin resistance, high triglycerides, low HDL and metabolic syndrome. It also rises with genetic hypercholesterolemia and the usual causes of high LDL.
What a low result can mean
Low LDL-P is associated with lower atherosclerotic risk and is a treatment target in some clinical practices.
What affects the result
Results differ between NMR and ion mobility methods and labs, so compare within the same method. Reducing refined carbohydrates, improving insulin sensitivity, weight loss and LDL-lowering drugs reduce LDL-P. ApoB measures a similar quantity (one ApoB per particle) and is more widely standardized.
Unit
Usually reported in nmol/L.
Also called on lab reports
LDL-P, LDL P, LDL Particle Count, LDL Particles, LDL-P (Total)
Related tests: Lipids & Cardiovascular Risk
This page is educational and does not replace advice from a healthcare professional.