High LDL Cholesterol

What does this result mean?

LDL (low-density lipoprotein) is often called the “bad” cholesterol because it deposits cholesterol in the artery walls and contributes to plaque build-up. A level above the reference range is a key driver of long-term cardiovascular risk. The significance of a raised LDL depends on how high it is and on the overall cardiovascular risk — blood pressure, diabetes, smoking, age, sex and family history — rather than the number alone. LDL is read as part of the full lipid profile.

Common reasons for the abnormal result

• A diet high in saturated and trans fats.
• Overweight and physical inactivity.
• Type 2 diabetes or prediabetes.
• An under-active thyroid (hypothyroidism).
• Kidney disease.
• Certain medicines — steroids, some diuretics, hormone therapy.
• Genetic (inherited) high cholesterol (familial hypercholesterolaemia), usually with very high LDL and a family history of early heart disease.

Why results must be interpreted in clinical context

A single raised LDL reading is best interpreted alongside HDL, triglycerides, total cholesterol, blood pressure, blood sugar, smoking status, weight and family history. The same LDL value carries different weight in someone with diabetes or a strong family history than in someone with no other risk factors. LDL is also sometimes calculated rather than measured directly, and can be less accurate when triglycerides are very high. A repeat fasting lipid profile and a full cardiovascular risk assessment place the result in context.

Relevant associated symptoms

Raised LDL causes no symptoms itself; it acts silently over years. The features that matter are those of associated conditions and risk — thirst and frequent urination suggesting diabetes, tiredness or cold intolerance suggesting an under-active thyroid, and a family history of early heart attacks or strokes. Most people with high LDL feel well, which is why it is found on testing.

Other tests that may be considered

A repeat fasting lipid profile is usually the first step. Depending on the overall picture, further tests may include blood sugar or HbA1c, thyroid function (TSH), kidney function, liver function, and a full cardiovascular risk assessment including blood pressure. A directly measured LDL may be used when triglycerides are very high.

When repeat testing may be appropriate

A repeat fasting lipid profile confirms the level and provides a baseline before any lifestyle or treatment change. Persistently raised LDL, or a very high level with a family history, warrants medical evaluation rather than self-management.

When medical evaluation is important

Medical evaluation is important when LDL remains raised, when it is very high, when it accompanies low HDL, high triglycerides, high blood pressure, diabetes, a strong family history of early heart disease, or when overall cardiovascular risk is raised. Treatment decisions — including whether medication is appropriate — are made by a doctor after a full risk assessment, not on the basis of a single number.

Related conditions

• High Cholesterol
• High Triglycerides
• Low HDL Cholesterol
• High Blood Sugar
• Abnormal Thyroid Function Tests

Related services

• Hypertension & Cardiovascular Risk
• Diabetes & Metabolic Health
• Thyroid Disorders
• Kidney Health
• Preventive Health & Health Check-ups