Why is particle number more important than cholesterol amount?

Each LDL particle can carry varying amounts of cholesterol. Someone with many small particles might have the same LDL-C as someone with fewer large particles, but the person with more particles has more "vehicles" that can deposit cholesterol in artery walls. Particle number (LDL-P) is a stronger predictor of cardiovascular events than LDL-C.

What causes small, dense LDL particles?

Insulin resistance is the primary driver. High triglycerides, metabolic syndrome, type 2 diabetes, excess refined carbohydrates, and visceral fat all promote the shift toward small, dense LDL. Improving insulin sensitivity through diet, exercise, and weight loss can shift particles back toward the healthier large, buoyant pattern.

How is this different from an ApoB test?

ApoB counts total atherogenic particles (one ApoB per particle). Lipoprotein fractionation goes further by breaking down particles into size subclasses, showing not just how many particles you have but what types. Both are valuable - ApoB is simpler and cheaper, fractionation provides more detail.

Should I get this test if my standard cholesterol is normal?

Consider it if you have metabolic syndrome, prediabetes/diabetes, high triglycerides, family history of early heart disease, or other risk factors despite normal LDL-C. Up to 50% of heart attacks occur in people with normal LDL cholesterol - particle testing helps identify hidden risk.

❤️ Heart Health

Lipoprotein Fractionation - Advanced Particle Testing

Name: Lipoprotein Fractionation - Advanced Particle Testing
Brand: Justlabs
SKU: 37847
Price: 52 USD
Availability: InStock

NMR Lipoprofile

Goes beyond standard cholesterol testing to measure the actual size and number of your LDL and HDL particles. Small, dense LDL particles are far more dangerous than large, fluffy ones.

Standard cholesterol tests measure the amount of cholesterol carried in lipoproteins, but not the particles themselves. Lipoprotein fractionation provides a detailed breakdown of your lipoprotein particles by size and concentration.

Why particle size matters: Two people with identical LDL cholesterol can have vastly different cardiovascular risk. Someone with many small, dense LDL particles has significantly higher risk than someone with fewer large, buoyant particles - even at the same LDL-C level.

Small, dense LDL particles:

Penetrate artery walls more easily
Are more susceptible to oxidation
Stay in circulation longer
Are strongly associated with metabolic syndrome and insulin resistance

This test helps explain why some people with "normal" cholesterol still have heart attacks, and why others with "high" cholesterol remain disease-free.

Price

$52

Results

3-5 business days

Lab Network

Quest

Fasting

9+ hrs

What's Measured

LDL Particle Number

Small LDL-P

HDL-P

LDL Size

HDL Size

What This Test Measures

This test provides a detailed breakdown of lipoprotein subclasses:

LDL Particles:

LDL particle number (LDL-P) - total count of LDL particles
Small LDL-P - the most atherogenic particles
LDL particle size - pattern A (large/buoyant) vs pattern B (small/dense)

HDL Particles:

HDL particle number (HDL-P)
Large HDL-P - most protective subclass
HDL particle size

Other markers may include:

VLDL subclasses
IDL (Intermediate density lipoprotein)
Lipoprotein(a) particle concentration

Who Should Consider This Test

Anyone wanting the most comprehensive assessment of lipid-related cardiovascular risk. Especially valuable for people with metabolic syndrome or insulin resistance, those with "normal" cholesterol but family history of heart disease, patients with discordant LDL-C and ApoB results, diabetics and prediabetics, anyone with high triglycerides (which shifts LDL toward small, dense particles), and those not responding as expected to statin therapy.

Health Insights

Conditions Screened

Cardiovascular disease riskAtherogenic dyslipidemiaMetabolic syndromeLDL pattern B (small dense LDL)Insulin resistance

Related Symptoms

Cardiovascular risk assessmentMetabolic syndrome evaluationFamily history of heart diseaseDiscordant lipid resultsTreatment optimization

When to Get Tested

Fasting for 10-12 hours is typically recommended for most accurate results. Best ordered alongside or after a standard lipid panel when more detailed risk assessment is needed. Useful for monitoring response to lifestyle changes or medication.

Fasting Required

This test requires fasting for accurate results. Please follow these instructions:

Do not eat or drink anything except water for 9-12 hours before your blood draw.
Water is allowed and encouraged - stay hydrated!
Schedule your lab visit in the morning for convenience.
Continue taking any prescribed medications unless advised otherwise by your doctor.

Understanding Your Results

LDL Particle Number (LDL-P):

Optimal: <1000 nmol/L
Moderate risk: 1000-1299 nmol/L
High risk: ≥1300 nmol/L

LDL Size Pattern:

Pattern A (large, buoyant): Lower risk
Pattern B (small, dense): Higher risk - associated with 3x increased heart disease risk

Key insight: If your LDL-C is normal but LDL-P is high, you have more particles than expected - this discordance increases risk. Focus on particle number, not just cholesterol content.

What to Expect

After placing your order, you'll receive an email from Rupa Health (our lab order partner) within 24 business hours to sign a consent form and schedule your blood draw at a Quest Diagnostics location.

The blood draw typically takes just a few minutes. Results are usually available within 3-5 business days and will appear in your secure Justlabs dashboard.

Our results include reference ranges and easy-to-understand indicators showing whether your values are within normal limits.