Markers · Cardiovascular
An ApoB of 117, flagged high. ApoB, read against the rest of you.
What ApoB measures, what it does in the body, why it's tested, and the two ranges it's read against. Everything said about the marker here comes from Merlin's own biomarker catalogue.
What ApoB is
ApoB is the single structural protein on every atherogenic lipoprotein particle - each LDL, VLDL, IDL, and Lp(a) particle carries exactly one ApoB. Because of that 1:1 relationship, ApoB measures the number of plaque-forming particles directly, whereas LDL-C estimates only the cholesterol cargo they carry. When the two disagree (common in insulin resistance, high triglycerides, or small-dense LDL), ApoB is the better read on cardiovascular risk.
What it does in the body
ApoB-100 is synthesized by the liver and is required to assemble and secrete VLDL; it remains on the particle through its conversion to LDL and mediates LDL binding to the hepatic LDL receptor for clearance. Each circulating atherogenic particle that can lodge in the arterial wall displays one ApoB molecule.
Why it's tested
ApoB is used to quantify atherogenic particle burden and refine cardiovascular risk beyond LDL-C, especially when LDL-C looks acceptable but triglycerides are high or particles are small and dense (discordance). It is increasingly a primary treatment target and a tool for monitoring response to lipid-lowering therapy.
The two ranges
The reference range reflects population statistics. The target reflects physiology.
- Lab reference range
- < 90 mg/dL (desirable); 90-109 mg/dL borderline; 110-129 mg/dL high; ≥ 130 mg/dL very high
- Functional target
- < 80 mg/dL (optimal); < 60 mg/dL for established cardiovascular disease or high risk
Those are different numbers, and you deserve to know which one you're looking at. Merlin reads your result against both.
Where this lives
A Field Guide to Atherosclerotic Risk
The field guide that covers ApoB in depth, whole and public.
In a real read
ApoB is the headline of the real Cardiovascular read on this site: 117 mg/dL, read beside particle number, triglycerides, hs-CRP, Lp(a), particle size and an ApoE genotype. Every one of them changes what the 117 means, and the read says how.
A real Cardiovascular surface from a real anonymized panel: the score, the narrative, the layers underneath. Yours will be built the same way, on your own numbers.
Educational context for your conversations with your licensed healthcare provider, not a diagnosis or a treatment plan. Merlin reads results; it doesn't diagnose.
Bring the panel this number came from. Merlin reads it against everything else you have, every system and every year, then shows you what it means and what's worth finding out next. Start with your first month.
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