Lab test glossary · Cholesterol & lipids
LDL Cholesterol: what it means
Also known as: LDL, low-density lipoprotein, bad cholesterol
LDL is the cholesterol fraction most associated with plaque buildup in arteries; lower is generally considered better for cardiovascular risk.
What it measures
LDL (low-density lipoprotein) carries cholesterol through the blood and can deposit it in artery walls, where over time it contributes to the plaque behind heart attacks and strokes. It's the number cardiovascular-risk decisions most often focus on.
On many reports LDL is calculated rather than measured directly, which is one reason it's interpreted alongside the rest of the lipid panel.
Typical range
There's no single 'normal' — target LDL depends on your overall cardiovascular risk. Below ~100 mg/dL is often considered optimal, and people at high risk may aim lower; your doctor sets the target for you.
Reference ranges differ between labs and are printed on your own report — always read your result against that range, not a general one.
What a high result can mean
- Diet high in saturated and trans fats
- Genetics, including familial hypercholesterolemia
- Reduced thyroid function, kidney or liver conditions
A high value is a starting point for a conversation, not a diagnosis — many causes are benign or temporary.
What a low result can mean
- Cholesterol-lowering medication (e.g. statins)
- Rarely, malnutrition or overactive thyroid
Why the trend matters
LDL guides long-term decisions, so the trajectory matters more than any one draw — it shows whether diet changes or medication are actually moving the number.
When to talk to your doctor
Discuss your LDL with your doctor in the context of your total cardiovascular risk, not as a standalone number — the same LDL can mean different things for different people.
Frequently asked questions
What is a good LDL level?
There's no single target — it depends on your overall cardiovascular risk. Below ~100 mg/dL is often considered optimal, and higher-risk people may aim lower. Your doctor sets the goal for you.
How can I lower LDL naturally?
A diet lower in saturated and trans fats, more fiber, exercise, and weight management can lower LDL. Genetics also play a large role, so some people need medication despite good lifestyle habits.
Is LDL or ApoB more important?
ApoB counts the actual number of artery-clogging particles and can be a sharper risk marker when it disagrees with LDL — which is why some clinicians order both.
This page is general education about a common lab test — it isn’t medical advice and can’t interpret your specific result. What a value means depends on your history, symptoms, and the rest of your labs, which is a conversation for you and your clinician.