§ Glossary · biology

ApoB

Apolipoprotein B — a count of atherogenic lipoprotein particles, increasingly preferred over LDL-C for cardiovascular risk.

Apolipoprotein B (ApoB) is the structural protein on every atherogenic lipoprotein particle (LDL, VLDL, IDL, Lp(a)) — exactly one ApoB per particle. So serum ApoB is a direct count of atherogenic particles, distinct from LDL-C which measures the cholesterol mass carried by those particles. The two can disagree (small dense LDL particles → low LDL-C, high ApoB; large LDL particles → high LDL-C, low ApoB) and outcome research consistently tracks ApoB more closely than LDL-C. Increasingly the recommended primary lipid risk marker.

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