An Lp(a) blood test measures Lipoprotein(a), a genetic "bad" cholesterol particle that significantly raises the risk for heart attack, stroke, and atherosclerosis (hardening of arteries), even with normal routine cholesterol levels.

It's often ordered for individuals with family histories of early heart disease or recurrent events, as levels are mainly inherited and don't change much with lifestyle. 

The test helps assess hidden cardiovascular risks not caught by standard lipid panels, with high levels indicating greater risk.

What it measures

• Lp(a): A particle similar to LDL ("bad") cholesterol, but carries more cholesterol and promotes plaque buildup in arteries.

• Genetic marker: Levels are primarily determined by your genes, making it a stable, lifelong risk factor. 

Why it's tested

• To assess risk for heart attack, stroke, or peripheral artery disease.

• For those with a strong family history of early heart disease or stroke.

• If routine cholesterol tests are normal but cardiovascular risk seems high.

• To understand unexplained heart issues or plaque buildup. 

What the results mean - estimated Atherosclerotic Cardiovascular Disease risk

Results reported in nmol/L (number of particles):

• Low < 100

• Moderate 100 – 200

• High 200 – 400

• Very high > 400

How it's done

• A simple blood draw is taken from your arm.

• Fasting (no food, smoking, or non-water drinks for 9-12 hours) may be required.

• It's a one-time test for many, but your doctor might repeat it to confirm or monitor changes (e.g., after menopause). 

Key takeaway

• Lp(a) testing identifies genetic risk for heart disease missed by standard tests, guiding proactive management for high-risk individuals.

Links

• Time to consider a vital new cholesterol test, Victor Chang Cardiac Research Institute

• Ask a cardiologist: Do I need an Lp(a) cholesterol test?, video, Victor Chang Cardiac Research Institute

• Lipoprotein (a): Levels & Testing, Cleveland Clinic

• Lipoprotein (a) | American Heart Association 

ApoB blood test

An ApoB (Apolipoprotein B) blood test measures the number of harmful, plaque-forming lipoprotein particles (LDL, VLDL) in your blood, serving as a superior, more direct marker for cardiovascular disease (CVD) risk than traditional LDL cholesterol testing. 

Elevated levels indicate a higher risk of heart disease and stroke. 

In Australia, Medicare does not cover ApoB blood tests.

Key Aspects of the ApoB Blood Test 

• What it Measures: ApoB is the primary protein component of all atherogenic (artery-clogging) lipoprotein particles. Because each particle contains exactly one ApoB molecule, this test directly counts these harmful particles.

• Why it is Done: It provides a clearer picture of cardiovascular risk, particularly for people with high triglycerides, diabetes, or a family history of heart disease. It is also used to monitor the effectiveness of lipid-lowering treatments, such as statins.

• Optimal Levels: 

  1. While results can vary, an optimal level in many contexts is considered to be below 0.8 g/L (or 80 mg/dL)

  2. Levels above 100-110 mg/dL100 are generally considered high-risk.

• Preparation: Fasting is often not strictly required, though it is best to check with the testing provider. 

ApoB vs. LDL Cholesterol 

• LDL-C (Conventional): Measures the total amount of cholesterol inside LDL particles.

• ApoB (Advanced): Measures the actual number of particles.

• The Difference: A person might have normal LDL cholesterol numbers, but if those particles are small and numerous, their ApoB will be high, indicating high risk. 

Managing High Results

If ApoB is high, lifestyle adjustments such as a heart-healthy (e.g., Mediterranean-style) diet and regular exercise may help, though medications like statins, ezetimibe, or PCSK9 inhibitors are often more effective for reduction. 

Links

• ApoB: A Better Marker for Cardiovascular Health, Everlab 

• Apolipoprotein B (APOB) Test, Cleveland Clinic 

Why both Lp(a) and ApoB tests are important