Cholesterol Results Explained: LDL, HDL, Triglycerides

Your results usually list four blood fats: total cholesterol, LDL, HDL and triglycerides, often with the lab's reference range beside them. Whether a number is right for you depends on your overall risk of heart attack and stroke, not on that range alone. You can keep the reports in a folder, or add them to the Health Vault in Sam, which reads these values once you agree and, if both reports print the same unit, shows the biggest changes since your previous report.

What do the lines on a cholesterol test mean?

Cholesterol is a fat in your blood, and the only way to know your level is a blood test. A lipid panel (or lipid profile) usually has these lines:

The 2019 European guideline from the ESC and EAS calls lowering LDL the primary target for reducing cardiovascular risk. HDL is often called the good cholesterol. But IQWiG, Germany's independent health institute, says more recent research has not confirmed a protective effect. Triglycerides affect risk too, though they play a smaller role when doctors estimate it. Why LDL can stay high even when you eat well is covered in High cholesterol despite a healthy diet.

IQWiG notes that risk does not suddenly jump above a certain cholesterol level. Medical societies also use different thresholds in places. And labs print results in mmol/L or mg/dL, so check the unit before you compare two reports.

Do you need to fast for a cholesterol test?

Usually not. The NHS says most people do not need to fast. Some are asked to avoid eating for up to 12 hours. European lipid and lab medicine societies (EAS and EFLM) agree. Their 2016 consensus statement says fasting is not routinely required for a lipid profile. The 2019 ESC/EAS guideline adds that non-fasting samples seem to have at least the same prognostic value for general risk screening.

Triglycerides are the exception worth knowing. After a meal they run about 0.3 mmol/L (27 mg/dL) higher on average. If a non-fasting result is above 5 mmol/L (440 mg/dL), the consensus statement suggests considering a repeat test while fasting.

Your clinic tells you what applies to your appointment. Fasting matters, for example, when a fasting blood sugar is taken at the same visit.

Why is your doctor's goal different from the lab's range?

The range on the report is usually the lab's general reference. Your goal is personal. The NHS calls its own table of cholesterol levels a guide for healthy adults. It says a good target depends on your age, any health conditions and your risk of cardiovascular disease.

Guidelines get to a personal goal in different ways:

• The European guideline (ESC/EAS) sets LDL goals by overall cardiovascular risk, in categories from low to very high. Its 2025 focused update left those goals unchanged. How strongly LDL should be lowered is still set by a person's level of risk.
• For people without cardiovascular disease, the German GPs' guideline (DEGAM, 2025) uses the overall risk of heart attack and stroke as the main basis for decisions, estimated with a validated score. Those decisions should be made together with the patient.
• The German Cardiac Society and several other medical societies did not agree with some of the DEGAM recommendations.

So two people with the same LDL result can be given different goals. Blood pressure, smoking and diabetes all feed into the risk estimate. Which goal applies to you is for your doctor to set.

A worked example: comparing two lab reports

Say your LDL was 3.6 mmol/L in March and 3.4 mmol/L in October. Both reports print the same range beside it.

In Sam, you photograph each report or upload the PDF. Once you agree, Sam reads the values, and you check the numbers before they are saved. Total cholesterol, LDL, HDL and triglycerides are among the 33 lab values Sam keeps by name. If a value sits above or below the range your lab printed, Sam shows that next to it. If no range is printed, Sam shows nothing.

If both of your last two reports print the same unit, Sam shows up to three of the biggest changes. If LDL is one of them, it reads 3.6 to 3.4, down 0.2. How to read that change and the 3.4 depends on your overall risk, and that belongs in the conversation with your doctor.

Three limits to know:

• If one lab prints mmol/L and the other mg/dL, Sam does not compare that line and does not convert units.
• Sam does not keep non-HDL cholesterol or Lp(a) as named values. If a report prints one of these lines, Sam usually keeps it under its printed name.
• Sam files some rows under the wrong value, for example VLDL cholesterol under total cholesterol. Check the name and number of every row against the original report.

How often is cholesterol checked?

Your doctor sets the interval. Some reference points:

• In England, the NHS Health Check is offered every five years to adults aged 40 to 74 and usually includes a cholesterol test. It is for people who do not already have conditions such as heart disease, diabetes, stroke or high blood pressure and are not on cholesterol-lowering medicine. People with one of these conditions should be offered regular check-ups instead.
• The NHS also suggests asking your GP surgery for a test if you have never had one. That applies if you are over 40, overweight, or have a family history of high cholesterol or heart problems.
• The 2019 European guideline says lipid screening should be considered in men over 40 and in women over 50 or after menopause.
• After treatment starts, the European guideline calls for monitoring because people respond differently. Your doctor sets the timing.

Lp(a) is where guidelines split. The ESC/EAS guideline says measuring it should be considered at least once in a lifetime. The DEGAM guideline says it should not be measured routinely on top of the usual risk factors to estimate risk. The German Cardiac Society and several other medical societies did not agree with that point. Whether it makes sense for you is a good question for your appointment.

Can an Apple Watch measure cholesterol?

No. Cholesterol can only be measured with a blood test. Apple's own support page lists high cholesterol among the conditions the Apple Watch ECG app cannot detect.

Sam does not measure cholesterol either. It reads values from lab reports you add yourself. Steps, active energy and exercise minutes from Apple Health appear in the same app. Sam does not link your activity to your lab values. Blood sugar is a similar story, covered in Can Apple Watch measure blood sugar?.

What should you bring to the appointment?

• Your latest lab reports. You create Sam's monthly report yourself, and it needs, among other things, notifications and Apple Health access. It lists the lab reports from that month with their dates; the values themselves are not in it.
• A current list of everything you take, including over-the-counter products. The post on what to put on a medication list sets it out.
• Whether a parent or sibling had a heart attack or stroke early in life. IQWiG names this as a risk factor.
• Your questions, for example about Lp(a) or your personal goal.

Before treatment starts, the DEGAM guideline says doctors should consider other causes of raised cholesterol. These include an underactive thyroid, poorly controlled diabetes, liver or kidney disease, heavy drinking and the effects of other medicines. That is why your doctor may order other blood tests. Sam also keeps values such as TSH, HbA1c, ALT and creatinine by name. For a wider list, see the doctor appointment checklist for a chronic condition.

Worried about taking cholesterol medicine?

If you have never had a heart attack, stroke or other cardiovascular disease, IQWiG says preventive medication is ultimately your decision. Your doctor can help you weigh it against your overall risk. People who have already had one of these, or who have inherited high cholesterol, are advised to take treatment.

Worries and possible side effects belong in a conversation with your doctor or pharmacist. Do not stop a prescribed medicine on your own.

In Sam's medication list, you set the name, strength and schedule. The catalog is a selection of common medicines, not a recommendation; for some entries a strength is prefilled, so check it against your pack. Which dose applies is for your doctor to decide. Sam reminds you at the times you set, and you tick off each dose. You can note how you feel in the symptom diary. Sam does not link those entries to a medicine and does not check interactions.

When is it an emergency?

High cholesterol does not usually cause symptoms. Chest pain or pressure, though, is always an emergency. Call your local emergency number straight away (112 in the EU, 999 in the UK, 911 in the US). It can feel tight or squeezing and spread to your arm, neck or jaw. Shortness of breath, sweating or feeling sick can come with it.

The same applies to possible stroke signs. These include one side of the face drooping, not being able to lift both arms, slurred speech or loss of sight. Call even if the signs have stopped. Do not wait for symptoms to pass.

Add your lab reports to Sam and compare the last two

You walk into the appointment with your own numbers instead of trying to remember them.

• Instead of a folder: photograph the report or upload the PDF to the Health Vault. Once you agree, Sam reads total cholesterol, LDL, HDL and triglycerides. Check name and number before saving: Sam files some rows under the wrong value, for example VLDL cholesterol under total cholesterol.
• Instead of flicking through pages: with the same unit on both reports, Sam shows up to three of the biggest changes and whether a value sits above or below the range your lab printed.
• Instead of a note on the fridge: the medication list reminds you at the times you set, and you tick off each dose.

Sam doesn't measure cholesterol, set a goal or calculate cardiovascular risk. More on the high cholesterol page.

Try Sam for free

Sam is a wellness companion, not a medical device. The app does not diagnose, treat, cure or prevent any disease or health condition. Always consult qualified professionals for medical decisions.

Related reading

• Medication list for your doctor: what to include
• Doctor appointment checklist for a chronic condition
• Can Apple Watch measure blood sugar?
• What to include in a doctor report
• Managing multiple conditions: appointments and records
• High Cholesterol but Eat Healthy? When It's Genetic

Sources

Updated: October 2026

• NHS: High cholesterol, Getting tested for high cholesterol and Cholesterol levels (all last reviewed 13 March 2026)
• NHS: NHS Health Check (last reviewed 14 August 2023)
• IQWiG (InformedHealth.org): High cholesterol (updated 24 September 2025)
• Mach F et al.: 2019 ESC/EAS Guidelines for the management of dyslipidaemias, Eur Heart J 2020;41:111-188
• ESC: 2025 Focused Update of the 2019 ESC/EAS Guidelines for the management of dyslipidaemias (31 August 2025)
• Nordestgaard BG et al.: Fasting is not routinely required for determination of a lipid profile, Eur Heart J 2016 (EAS and EFLM consensus statement)
• DEGAM: S3 guideline on GP cardiovascular risk counselling (Hausärztliche Risikoberatung zur kardiovaskulären Prävention), version 2.1, short version (2025, in German)
• Apple Support: Take an ECG with the ECG app on Apple Watch
• NHS: Heart attack (last reviewed 31 March 2026) and Stroke symptoms (last reviewed 12 September 2024)
• MedlinePlus (US National Library of Medicine): When you feel like changing your medicine (reviewed 4 September 2024)