A visual guide to the topic

Inheritance

What does Lp(a) add to assessment?

Overall risk

How does it fit with other risk factors?

Evidence

Does lowering the marker improve outcomes?

Visual summary of the concepts developed and referenced in this article. This is an educational diagram, not a diagnostic tool or a universal sequence of tests.

Why is Lp(a) different?

Lipoprotein(a), or Lp(a), resembles an LDL particle but also carries apolipoprotein(a). The concentration is largely determined by genetics and usually remains relatively stable through adulthood.

How does it relate to risk?

Genetic and epidemiologic evidence supports elevated Lp(a) as a causal risk factor for atherosclerotic cardiovascular disease and calcific aortic valve stenosis. Risk rises across the concentration range; there is no perfect biological line between “normal” and “abnormal.”

Who should be tested?

The 2026 ACC/AHA dyslipidemia guideline recommends that Lp(a) be measured at least once in adulthood. The 2025 ESC/EAS update says at least one adult measurement should be considered in Europe. The result is especially relevant with premature cardiovascular disease, a strong family history, familial hypercholesterolemia, or risk that appears greater than standard factors explain. Local guidance should inform interpretation.

What is considered high?

U.S. and NLA guidance identifies 125 nmol/L or 50 mg/dL and above as elevated or risk-enhancing. European guidance uses a different molar threshold: above 50 mg/dL, with reference to above 105 nmol/L, as a risk modifier. These are jurisdiction-specific thresholds, not fixed conversions or predictions that an event is inevitable.

Are mg/dL and nmol/L interchangeable?

No—not precisely. The units measure different properties, and a fixed conversion can be inaccurate because apolipoprotein(a) particle size varies. Use the unit reported by the laboratory.

Does the 2026 result change what I should do?

On September 4, 2026, the sponsor announced that Lp(a)HORIZON did not meet its primary cardiovascular endpoint in the overall study population, despite lowering Lp(a) with pelacarsen. The announcement did not provide the complete analysis, event rates, effect estimates, or subgroup results.

The news should not prompt you to abandon cardiovascular risk assessment or change prescribed medication yourself. Identifying a risk factor is different from demonstrating that a particular treatment improves health. A useful question for your appointment is: “How does my Lp(a) result change my overall risk assessment and prevention plan?”

What happens if the level is elevated?

Do not self-treat. The practical response is to refine risk and address modifiable factors—such as LDL-C, blood pressure, smoking, diabetes, nutrition, and physical activity—through an individualized prevention plan. Treatment claims should be tied to complete clinical outcome evidence and regulatory status, not to a biomarker change alone.

Questions for your appointment

  • Does this result change a decision in my situation?
  • Are there other risk factors we should assess or address?
  • Should we discuss testing close family members?

Explore further with MERHI ONE

See the comparison of Lp(a), LDL-C, and ApoB to understand what each marker adds. The guide also covers regional recommendations and the limits of current treatment evidence.

Key references