LDL Cholesterol
Low-density lipoprotein – the 'bad' cholesterol
Also known as
Definition
LDL cholesterol (low-density lipoprotein) transports cholesterol from the liver to body cells and is the primary driver of atherosclerosis when chronically elevated. Risk stratification is individualized using SCORE2 tables (ESC) based on overall risk profile. Beyond absolute concentration, particle quality metrics (ApoB, small dense LDL) are gaining increasing diagnostic relevance.
| Parameter | Value |
|---|---|
| Unit | mg/dl (mmol/l) |
| Reference Range | < 130 mg/dl (low risk) | < 100 mg/dl (moderate risk) | < 70 mg/dl (high risk) |
| Optimal Range (lab2go) | < 100 mg/dl (lab2go Optimum Zone for general prevention) |
Conversion: 1 mg/dl × 0.02586 = mmol/l. US labs report LDL in mg/dl; international studies also use mmol/l. ESC thresholds reference mg/dl.
↓ What a low value means
Very low LDL (< 40 mg/dl) achieved through statin therapy or PCSK9 inhibitors is cardiovascularly advantageous and targeted in very high-risk patients. Extremely low LDL (< 20–25 mg/dl) without medication may indicate rare disorders (abetalipoproteinemia, hypobetalipoproteinemia) or severe malnutrition. Large statin trials have not demonstrated safety concerns from very low LDL.
↑ What a high value means
LDL > 130–160 mg/dl without additional risk factors: elevated long-term risk; lifestyle intervention recommended. LDL > 190 mg/dl: suspect familial hypercholesterolemia (FH); drug therapy usually required. Causally linked to atherosclerosis progression, heart attack, and stroke — cumulative lifetime LDL exposure is the key determinant.
✓ How to optimize this marker
Diet: reduce saturated fat to < 10% of calories, eliminate trans fats; increase soluble fiber (oat beta-glucan, legumes, psyllium lower LDL 5–10%); plant sterols/stanols (2 g/day) lower LDL 8–10%; Mediterranean diet. Exercise: aerobic training. Weight loss. Pharmacotherapy for elevated risk: statins (first-line), ezetimibe, PCSK9 inhibitors.
When to test
In the fasting lipid panel (12-hour fast) alongside triglycerides, HDL, and total cholesterol for most accurate calculation (Friedewald formula). Direct LDL measurement is also possible non-fasting. First screening at age 35 (men) / 45 (women), earlier with risk factors. Follow-up on therapy: after 6–8 weeks, then every 6–12 months.
Frequently asked questions
What is the difference between LDL and ApoB? +
LDL cholesterol measures the amount of cholesterol within LDL particles. ApoB measures the number of particles. With small, dense LDL particles, LDL-C can be normal while ApoB is elevated — the discordance phenomenon that underestimates true risk.
Are statins necessary for everyone with elevated LDL? +
No. The indication depends on overall risk (SCORE2 calculator, age, blood pressure, smoking, diabetes, family history). With low overall risk, lifestyle changes are often sufficient. Pharmacotherapy is recommended for high or very high risk.
Do eggs raise LDL? +
In most people, moderate egg consumption (1–2 eggs/day) raises LDL minimally. Hyper-responders (~25% of the population) show a larger increase. Saturated fats in processed meat and butter have a far greater impact on LDL than dietary cholesterol from eggs.
Sources
Last Reviewed: May 28, 2026 · sina
This information is for orientation only and does not replace medical advice. Reference ranges can vary by laboratory, method and country.