Part 2 of The 2026 ACC/AHA Multisociety Guideline on Dyslipidemia

The 2026 ACC/AHA Multisociety Guideline on Dyslipidemia recognizes apoB as a superior marker in specific scenarios — it directly counts the number of atherogenic particles (LDL + others like VLDL/remnants/Lp(a)), making it more accurate than LDL-C (which measures cholesterol mass inside particles) for predicting cardiovascular risk, especially in cases of discordance (LDL-C looks good but apoB is still high).This discordance is common in high-risk groups: people with ASCVD, CKM syndrome, type 2 diabetes, elevated triglycerides (≥150–200 mg/dL), obesity/metabolic issues, or on statins where small/dense particles persist. In those settings, apoB often better identifies residual risk and supports intensifying therapy (e.g., adding ezetimibe, bempedoic acid, PCSK9 inhibitors, or inclisiran).However, the guideline does not recommend switching to apoB as the primary/single marker for everyone — including in low- or intermediate-risk primary prevention or as the default over LDL-C. Here's why, based on the guideline's rationale and supportive text:LDL-C remains the foundational target — Decades of large randomized controlled trials (RCTs) with statins, ezetimibe, PCSK9 inhibitors, etc., show clear event reduction tied to lowering LDL-C (and % reduction + absolute goals like <100 mg/dL intermediate risk, <70 mg/dL high risk, <55 mg/dL very high-risk/ASCVD). These trials used LDL-C (or non-HDL-C) as the primary metric, not apoB. No equivalent large outcome trials exist with apoB as the main treatment target or primary endpoint.ApoB is an adjunct tool (Class 2a recommendation — reasonable/may be beneficial) — It's selectively recommended after LDL-C and/or non-HDL-C goals are met in treated high-risk patients to check for hidden residual risk and guide further intensification. It's not for routine initial screening, untreated patients, primary prevention broadly, or pediatrics. The guideline prioritizes LDL-C for starting therapy and broad monitoring.Practical and evidence limitations — While apoB is standardized, fasting-independent, and widely available, universal adoption lacks strong RCT support for changing outcomes beyond what's achieved with LDL-C goals. In many people (especially without metabolic issues), LDL-C and apoB correlate closely — discordance is the exception, not the rule (~20% in some high-risk groups). Non-HDL-C often serves a similar role as a simpler alternative.Broader framework — The guideline emphasizes lifetime exposure to atherogenic lipids, with LDL-C as the core driver in causal evidence. ApoB enhances personalization in tricky cases (e.g., CKM/obesity where small particles dominate), but doesn't replace the established LDL-C system for most decisions.In short: ApoB is excellent (and often better) where discordance or metabolic complexity exists — and the guideline pushes its use more than before in those groups