Biomarker Glossary

Cholesterol

Cholesterol is a fatty substance carried in your blood that your body uses to build cells and hormones. A cholesterol blood test measures total cholesterol, HDL (good cholesterol), LDL (bad cholesterol) and triglycerides, and is the standard UK test for assessing cardiovascular risk.

Also known as: Total Cholesterol, TC, Lipid Profile

Cholesterol is most informative when read alongside related markers like Triglycerides and HbA1c. A single number rarely tells the whole story. If your reading sits outside the typical range, share the full report with your GP or healthcare professional before drawing conclusions.

What is Cholesterol?

Cholesterol is a waxy, fat like substance made in the liver and absorbed from some foods. Your body needs it to build cell membranes, produce hormones (including testosterone, oestrogen and cortisol) and make vitamin D and bile acids.

Cholesterol does not dissolve in blood. It travels around the body inside protein parcels called lipoproteins. The two most important are LDL (low density lipoprotein, often called bad cholesterol) which can build up in artery walls, and HDL (high density lipoprotein, the good cholesterol) which transports cholesterol back to the liver for disposal.

A standard UK lipid profile measures total cholesterol, HDL, LDL (often calculated), triglycerides, and the total cholesterol to HDL ratio. Together these markers give a more accurate picture of cardiovascular risk than total cholesterol alone.

Why test Cholesterol?

To assess your risk of cardiovascular disease, heart attack and stroke.
If you have a family history of high cholesterol or early heart disease.
To monitor the effect of diet, weight loss, exercise or statin medication.
As part of a routine health check from your 40s onwards (the NHS offers free checks every 5 years from age 40 to 74).

To assess your risk of cardiovascular disease, heart attack and stroke.

Cholesterol normal range (UK)

Result	What it means
Total cholesterol: below 5.0 mmol/L	Healthy
Total cholesterol: 5.0 to 6.5 mmol/L	Borderline
Total cholesterol: above 6.5 mmol/L	High
HDL (good): above 1.0 mmol/L (men), above 1.2 mmol/L (women)	Healthy
LDL (bad): below 3.0 mmol/L	Healthy. Below 2.0 mmol/L if at high cardiovascular risk.
Total cholesterol to HDL ratio: below 4.0	Lower cardiovascular risk

UK ranges based on NHS and Joint British Societies guidance. Target ranges are lower for people with diabetes, established heart disease or other high risk conditions.

About these ranges. The ranges above are typical UK clinical lab ranges aligned to NHS and Royal College of Pathologists guidance. Your Chxhealth report will show the specific reference range used by our partner lab, Randox, for each marker. Lab ranges vary slightly between providers and assays. Always interpret your results in the context of the range printed on your own report.

What causes high Cholesterol?

Diet high in saturated fat, trans fat or refined carbohydrates
Being overweight or having central (abdominal) obesity
Lack of physical activity
Smoking and excess alcohol
Familial hypercholesterolaemia (an inherited condition)
Hypothyroidism (underactive thyroid)
Type 2 diabetes and insulin resistance
Kidney or liver disease
Certain medications including steroids and some diuretics

What causes low Cholesterol?

Hyperthyroidism (overactive thyroid)
Malabsorption conditions such as coeliac disease
Severe liver disease
Malnutrition
Some genetic conditions (rare)
Critical illness or severe infection

Symptoms of high Cholesterol

High cholesterol usually has no symptoms. It is often called a silent risk factor.
In familial hypercholesterolaemia, visible signs may appear: yellow fatty deposits around the eyes (xanthelasma), tendon lumps (xanthomas), or a pale ring around the iris.
The first sign is often a cardiovascular event such as chest pain (angina), heart attack or stroke, which is why screening matters.

Symptoms of low Cholesterol

Very low cholesterol is uncommon and usually reflects another underlying problem rather than being symptomatic itself.
Possible associations include depression, anxiety and increased infection risk in severe cases.

How is Cholesterol tested?

Cholesterol is measured from a small blood sample, either by finger prick at home or by a clinic blood draw.

For a full lipid profile including accurate triglycerides, the NHS still recommends a 9 to 12 hour fast before the test. Non fasting tests are increasingly accepted for total cholesterol and HDL alone.

Chxhealth samples are analysed by Randox, a UK laboratory accredited by UKAS. Results return in 3 to 5 working days.

How to support healthy Cholesterol levels

Reduce saturated fat (fatty cuts of meat, butter, full fat dairy, processed foods) and replace with unsaturated fats (olive oil, nuts, avocado, oily fish).
Eat more soluble fibre. Oats, beans, lentils, apples and pears all help lower LDL.
Include 2 portions of oily fish per week (salmon, mackerel, sardines).
Aim for 150 minutes of moderate exercise per week. Both aerobic activity and strength training improve HDL.
Lose weight if needed. Even a 5 to 10 percent reduction in body weight typically lowers LDL.
Stop smoking. Smoking lowers HDL and damages artery walls directly.
Limit alcohol to no more than 14 units per week, spread over several days.

These are general lifestyle suggestions. Chxhealth is an information service. For personal medical advice, please speak to a healthcare professional.

Chxhealth panels that test Cholesterol

17 Chxhealth biomarker panels include Cholesterol. Each is analysed by Randox, a UK laboratory accredited by UKAS. Reports are delivered in 3 to 5 working days.

Cholesterol FAQs

What is a healthy cholesterol level in the UK?

Total cholesterol below 5.0 mmol/L, LDL below 3.0 mmol/L, HDL above 1.0 mmol/L for men and 1.2 mmol/L for women, and a total cholesterol to HDL ratio below 4.0. People at higher cardiovascular risk are usually advised to aim lower, particularly for LDL.

Do I need to fast for a cholesterol test?

For a full lipid profile including triglycerides, the NHS still recommends fasting for 9 to 12 hours (water only). Non fasting tests are acceptable for total cholesterol and HDL but triglycerides will be less accurate.

Can lifestyle changes really lower cholesterol?

Yes. Diet and exercise can lower LDL by 10 to 20 percent for most people. Statin medication is usually needed for larger reductions or when cardiovascular risk is high.

What does the total cholesterol to HDL ratio mean?

It is one of the strongest single predictors of cardiovascular risk. A ratio below 4.0 is considered healthy. The lower the better.

Should I worry about high cholesterol if I feel well?

Yes. High cholesterol has no symptoms but it raises long term risk of heart attack and stroke. The earlier you identify and address it, the more options you have.

Often tested with Cholesterol

The biomarkers below are commonly investigated alongside Cholesterol because they reveal connected aspects of the same physiological picture:

Triglycerides: The other half of the standard lipid panel.
HbA1c: Cardiometabolic risk is best assessed across glucose and lipids together.
ALT: Fatty liver often coexists with elevated cholesterol and triglycerides.
GGT: Sensitive marker for fatty liver linked with lipid dysregulation.

Choose the right test for your goal

If you are reading about Cholesterol because of a specific health goal, our buying guides walk you through which Chxhealth panels fit:

Sources and further reading

This page is informed by guidance from the NHS, NICE, Royal College of Pathologists and other UK authoritative bodies. For deeper detail or to verify the information, see:

About this page. Last reviewed: 13 May 2026. Next scheduled review: May 2027. This page has not yet been independently reviewed by a clinician. It is written from authoritative UK medical guidance (NHS, NICE, Royal College of Pathologists, peer-reviewed sources) but has not undergone formal clinical sign off.

Important. Chxhealth is a UK information service. We do not diagnose, treat or prescribe. The reference ranges and information on this page are general educational content and should not be used as a substitute for advice from a qualified healthcare professional. For any concerns about your health or results, please speak to your GP or another healthcare professional.