Expert Insights: Lp(a) and ApoB in the 2026 Dyslipidemia Guidelines

A pair of underutilized biomarkers, lipoprotein(a) [Lp(a)] and apolipoprotein B (apoB), receive substantially elevated clinical standing in the 2026 ACC/AHA Dyslipidemia Guideline, reflecting a growing evidence base for their roles in residual cardiovascular risk and lipid-related disease burden.

For the first time in a US guideline, universal Lp(a) measurement is recommended at least once in all adults, carrying a Class I designation. Ann Marie Navar, MD, PhD, a writing committee member and cardiovascular prevention specialist, explains the 125 nmol/L threshold (approximately 50 mg/dL) represents a meaningful inflection point, above which cardiovascular risk increases substantially, reaching levels comparable to heterozygous familial hypercholesterolemia at concentrations of 300–400 nmol/L. Because Lp(a) is inherited in an autosomal dominant pattern, elevated levels should prompt cascade screening among first-degree relatives.

While Lp(a)-specific treatment targets cannot yet be established due to limited outcomes data, the guideline recommends intensification of overall lipid-lowering therapy and aggressive control of all coexisting risk factors in affected patients.

ApoB is introduced into the US guideline for the first time as a recommended measurement, particularly in patients with diabetes, hypertriglyceridemia, or very low LDL cholesterol, populations in whom standard LDL estimation may underrepresent true lipid-related risk. Because apoB directly quantifies the number of atherogenic lipoprotein particles rather than their cholesterol content, it offers a more precise risk signal in patients with cholesterol-depleted particles.

For those achieving LDL and non-HDL targets but retaining elevated apoB, the guideline recommends further intensification of therapy. Numeric apoB goals conveniently align with LDL targets: less than 55, 70, or 90 mg/dL, depending on risk category. Navar also highlights apoB's practical advantages—it is directly measured rather than calculated, is not meaningfully affected by fasting status, and remains reliable in settings where LDL estimation is prone to error.

Morris has no relevant disclosures to report. Navar reports disclosures with Amge, Arrowhead Pharmaceuticals, AstraZeneca, Bayer, Eli Lilly and Company, Esperion, Johnson & Johnson, Merck, Miga Health, NewAmsterdam Pharma, Novartis, Novo Nordisk, Sanofi, and Silence Therapeutics, among others.

References:

1. Blumenthal RS, Morris PB, Gaudino M, et al. 2026 ACC/AHA/AACVPR/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Dyslipidemia: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. J Am Coll Cardiol. Published online March 13, 2026. doi:10.1016/j.jacc.2025.11.016
2. American College of Cardiology. ACC/AHA Issue Updated Guideline for Managing Lipids, Cholesterol - American College of Cardiology. American College of Cardiology. Published March 13, 2026. Accessed March 23, 2026. https://www.acc.org/About-ACC/Press-Releases/2026/03/13/18/01/ACCAHA-Issue-Updated-Guideline-for-Managing-Lipids-Cholesterol