HDL and LDL are different lipoproteins that carry cholesterol in the blood. LDL is often called “bad” cholesterol because high levels can contribute to plaque in arteries. HDL is often called “good” cholesterol because it carries cholesterol back to the liver for removal. The comparison helps explain a lipid report, but neither label is a diagnosis or a personal treatment target.
The CDC's official explanation of HDL, LDL and triglycerides describes these roles. The National Heart, Lung, and Blood Institute and NHS guidance provide further context on cholesterol, testing and interpreting a result. These pages were checked on 8 November 2026. The aim here is to understand the terms before discussing the actual report with a qualified doctor.
| Report term | Meaning |
|---|---|
| LDL | Low-density lipoprotein, often labelled bad cholesterol |
| HDL | High-density lipoprotein, often labelled good cholesterol |
| Total cholesterol | The overall amount of cholesterol in the blood |
| Non-HDL cholesterol | Total cholesterol minus HDL cholesterol |
| Triglycerides | A different type of blood fat used for energy |
What is the difference between HDL and LDL cholesterol?
Cholesterol needs transport through the bloodstream. Lipoproteins combine fats and proteins and carry it around the body. LDL and HDL describe different carriers, which is why the abbreviations appear separately on a lipid report. A lipid profile can therefore provide more information than a single total cholesterol number.
CDC says that when there is too much LDL cholesterol, cholesterol can build up on blood vessel walls. This forms plaque, which narrows the inside of arteries over time. The process is called atherosclerosis and can increase the risk of heart disease and stroke. The relevant issue is the effect of excessive levels, not whether the word cholesterol appears on a food label.
HDL absorbs cholesterol in the blood and takes it back to the liver, where it can be removed from the body. CDC says higher HDL levels can lower the risk of heart disease and stroke. That describes a relationship used in health assessment. It does not mean a reader should interpret HDL alone or assume a favourable label makes the rest of the report irrelevant.
Is all cholesterol bad for health?
No. The National Heart, Lung, and Blood Institute's blood cholesterol guide explains that cholesterol is a waxy, fat-like substance the body needs for good health in the right amounts. It also says inherited genes and lifestyle habits play a major role in cholesterol levels.
This helps explain why a lipid report is not a simple judgment about what someone ate recently. Family history matters, and a doctor considers the wider health picture. The biochemical terms describe what is being measured; they do not, by themselves, explain every reason for an individual's result.
What are triglycerides and non-HDL cholesterol?
Triglycerides are another type of fat in the blood, used by the body for energy. They are not simply a different spelling of cholesterol. CDC says a combination of high triglycerides with low HDL or high LDL can increase the risk of health problems such as heart attack. This is one reason a clinician may review the whole panel.
Non-HDL cholesterol is a calculation. The NHS cholesterol results page defines it as the difference between total cholesterol and HDL. Read the label carefully: non-HDL is not another name for LDL, and a report may show both values.
For an arithmetic example only, suppose a fictional report lists total cholesterol as 200 mg/dL and HDL as 50 mg/dL. Non-HDL would be 150 mg/dL, found by subtraction. These invented numbers illustrate the calculation and are not a healthy-range recommendation or an assessment of anyone's result.
What is a normal HDL or LDL level?
A useful personal target needs clinical context. NHS guidance says the appropriate level depends on age, existing health conditions and cardiovascular risk. A doctor uses cholesterol results alongside factors such as blood pressure and health history. A single number copied from another person's report is not enough to establish the right goal.
Check the measurement unit as well as the number. CDC presents cholesterol in mg/dL, while the NHS results page uses mmol/L. These scales cannot be compared by placing the raw numbers beside one another. Keep the units with any value you discuss, and use the reference information provided with your own laboratory report.
Do I need to fast for a cholesterol test?
The NHS testing guide says most people do not need to fast, although some may be asked to do so before a test. Follow the instructions given by the laboratory or clinician for the particular test being requested. Do not infer preparation requirements from an old report or an online comparison.
High cholesterol usually does not cause symptoms, so feeling well cannot confirm a healthy result. If you have a medical condition, a family history of cholesterol problems or questions about your results, consult a qualified doctor. Our related guides cover saturated and unsaturated fats, reading food labels in India and why high blood pressure can feel silent.
