ApoB vs. LDL — which one should I be tracking?

LDL cholesterol measures the total cholesterol content of LDL particles, while ApoB counts the total number of atherogenic lipoprotein particles (LDL, VLDL, IDL, and Lp(a)), ApoB predicts cardiovascular events more accurately than LDL-C because particle count, not cholesterol concentration, determines how many particles can penetrate arterial walls; the Emerging Risk Factors Collaboration analysis of 302,430 individuals found ApoB superior to LDL-C in almost all cardiovascular risk prediction contexts (Sarwar et al., JAMA, 2009).

The clinical guideline situation: current US guidelines (ACC/AHA 2018) still primarily use LDL-C and non-HDL-C for treatment targets, with ApoB as an "alternative" marker. European guidelines are more explicit about ApoB superiority. The practical answer for men who can access both tests: use ApoB as your primary treatment target (below 80 mg/dL for average risk, below 65 mg/dL for high risk) and LDL-C as the secondary reference. In men with discordance (low LDL-C but high ApoB), ApoB is the clinically correct guide.

Honesty Scale: Solid (1) for ApoB superiority over LDL-C in large meta-analytic data.

What to do: If your LDL-C is "acceptable" (below 130 mg/dL) but you have metabolic risk factors (elevated triglycerides, low HDL, central obesity, insulin resistance), request ApoB. A result above 90 mg/dL in a man with these risk factors warrants statin or other lipid-lowering therapy regardless of LDL-C.

For the full picture, read The ApoB/Lp(a)/Lipids Deep Dive