LDL Particle Size levels: what's normal, high and low
The average diameter of your LDL particles. Larger is generally healthier.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
The short answer
LDL Particle Size is measured with a standard blood draw after an 8–12 hour fast. A typical reference range is 20.6 – 22.0 nm. At TestWell it's $90.99 all-in as Advanced Lipid Panel, results in 3–5 business days, drawn at Quest. An out-of-range result is a prompt to look closer, not a diagnosis.
- Units
- nm
- Sample
- Blood draw
- Fasting
- 8–12 hours
- Results
- 3–5 business days
- Price
- $90.99
- Labs
- Quest
LDL Particle Size Reference Range
These are the typical adult reference ranges used by major US labs. Your report will include the specific range used by the lab that processed your sample.
| Population | Range |
|---|---|
| age 18+ | 20.6 – 22.0 nm |
Reference ranges are educational. Always interpret your result with the specific range printed on your lab report and discuss anything outside the range with a clinician.
Have a result in hand? analyze it with your AI assistant using these reviewed ranges, or run it through our explainer. Tools: look up another marker's range · convert lab units
What your LDL Particle Size result may mean
Smaller LDL particles (<20.5 nm) are more atherogenic and often linked to insulin resistance.
What a low LDL Particle Size means: causes, symptoms, next steps ↓Educational only — not a diagnosis. Many factors can influence a single result. Discuss anything that concerns you with a healthcare provider.
What does a low LDL Particle Size mean?
Small LDL particles (below about 20.5 nm — 'pattern B') are more atherogenic than large ones: they enter the artery wall more easily and oxidize faster. Small size is driven almost entirely by high triglycerides and insulin resistance; it is the lipid signature of metabolic syndrome and type 2 diabetes. Lowering triglycerides shifts particles larger within months.
Common causes of a low LDL Particle Size
- Insulin resistance, prediabetes, type 2 diabetes, central obesity
- High triglycerides, low HDL
- Refined-carbohydrate diets, inactivity
- Genetic pattern B phenotype
- Hypothyroidism
Ordered from most to least common.
Symptoms that can go with it
- None
What clinicians usually check next
- Triglycerides, fasting insulin or A1c, ApoB (the particle count matters more than size for risk decisions)
- Lifestyle changes aimed at triglycerides; retest in 3–6 months
- Cardiovascular risk review with a clinician
Does LDL particle size matter if my ApoB is normal?
Less than people think — particle number (ApoB or LDL-P) carries most of the risk information. Small size mainly tells you insulin resistance is present, which is itself worth acting on.
Educational only — not a diagnosis. A single result outside the range is a prompt to look closer with a clinician.
How do you get a LDL Particle Size test?
Order online, a licensed physician reviews the requisition, and you walk into a nearby lab for the draw. LDL Particle Size is available on its own or inside these panels — panels cost less per marker when you want the fuller picture.
| Option | Includes | Price |
|---|---|---|
| Advanced Lipid Panel | This marker only | $90.99 |
Quest vs. Labcorp for LDL Particle Size: which lab should you pick?
Both are CLIA-certified national labs and the result is clinically equivalent, so pick whichever location is closer. Your report will print that lab's own reference range, which can differ slightly from the table above.
| Lab | Available | Price |
|---|---|---|
| Quest Diagnostics | Yes | $90.99 |
| Labcorp | No | — |
| BioReference (NY & NJ) | No | — |
Need help choosing a location? Use the lab finder to see draw sites near your ZIP.
Related Heart Health biomarkers
Markers commonly tested alongside LDL Particle Size.
Frequently asked
What does a low LDL Particle Size mean?
Small LDL particles (below about 20.5 nm — 'pattern B') are more atherogenic than large ones: they enter the artery wall more easily and oxidize faster. Small size is driven almost entirely by high triglycerides and insulin resistance; it is the lipid signature of metabolic syndrome and type 2 diabetes. Lowering triglycerides shifts particles larger within months.
Does LDL particle size matter if my ApoB is normal?
Less than people think — particle number (ApoB or LDL-P) carries most of the risk information. Small size mainly tells you insulin resistance is present, which is itself worth acting on.
Do I need a doctor's order to test my ldl particle size?
No. TestWell's licensed physician network reviews and approves your order — usually within minutes. You can place an order online without an in-person visit or a referral from your own doctor.
How long does it take to get LDL Particle Size results?
Most LDL Particle Size results are available in 1–3 business days after your specimen arrives at the lab. You'll get an email the moment your results are ready, with everything viewable in your TestWell portal.
How much does a LDL Particle Size test cost?
Our Advanced Lipid Panel starts at $90.99. That's the all-in price — no copays, no insurance hoops, no surprise bills. HSA and FSA cards are accepted.
Do I need to fast before my LDL Particle Size test?
Yes — for the most accurate result, fast for 8–12 hours before your blood draw. Water is fine; coffee, food, and supplements are not. Your prep instructions will be included with your order.
Which lab will process my LDL Particle Size test?
Your test will be processed by Quest Diagnostics, Labcorp, or BioReference depending on which is closest to you and which lab carries the test. All three are CLIA-certified and trusted by hospitals nationwide. You'll choose your lab during checkout from 4,000+ locations.
Ready to test your ldl particle size?
Order in two minutes, get physician-approved, and visit a lab the same day. Starts at $90.99.