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 | Labs state different assessment ranges for LDL cholesterol; the range on your own report is what counts, and your doctor interprets the result. Target values that guidelines give according to cardiovascular risk are not reference ranges. |
Agree on your personal target range with your doctor.
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 usually occurs during therapy with statins or PCSK9 inhibitors and goes along with lower cardiovascular risk. Extremely low LDL 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
Elevated LDL means an elevated long-term risk. Very high values may point to familial hypercholesterolemia (FH). LDL is causally involved in atherosclerosis progression, heart attack, and stroke; cumulative lifetime LDL exposure is the key determinant. The 2019 ESC/EAS guideline sets treatment goals by risk category, for example below 100 mg/dl at moderate and below 70 mg/dl at high risk. Whether treatment is given and which of these goals applies is decided by your doctor based on overall risk; they are not normal or reference values.
✓ What can influence this value
The LDL value is influenced by genetic predisposition (e.g., familial hypercholesterolemia), diet, body weight, and physical activity. Saturated fats and trans fats can raise the value; soluble fiber (e.g., oat beta-glucan, legumes) and plant sterols can lower it. Lipid-lowering medications such as statins, ezetimibe, or PCSK9 inhibitors also change the value markedly. The assessment is made by the treating doctor.
When to test
LDL is measured in the lipid panel together with triglycerides, HDL, and total cholesterol; for calculation with the Friedewald formula, labs usually ask for a fasting period. Direct LDL measurement is also possible non-fasting. It is measured at checkups, with risk factors, and during lipid-lowering therapy. How often it is measured is decided by your doctor.
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.
What determines whether elevated LDL is treated? +
Overall cardiovascular risk. Factors taken into account include the SCORE2 calculator, age, blood pressure, smoking, diabetes, and family history. Whether and how treatment is given is decided by your doctor.
Do eggs raise LDL? +
In most people, moderate egg consumption raises LDL minimally. Some people (hyper-responders) show a larger increase. Saturated fats in processed meat and butter have a far greater impact on LDL than dietary cholesterol from eggs.
LDL Cholesterol
Sources
Last updated: May 28, 2026
This information is for orientation only and does not replace medical advice. Reference ranges can vary by laboratory, method and country.