Apolipoprotein B
Also written as: ApoB, Apo B
A count of cholesterol carrying particles - one ApoB protein sits on each particle.
What it measures
The concentration of apolipoprotein B, a protein present as exactly one copy on each LDL, VLDL, IDL (an intermediate particle between the two), and lipoprotein(a) particle. It therefore acts as a count of the particle types linked with artery buildup.
Why a doctor orders it
Ordered to count cholesterol carrying particles directly, which can tell a different story from the cholesterol amount alone. It is often used when triglycerides are elevated or when standard panel results seem inconsistent with each other.
What is generally associated with a higher result
Broadly associated with a larger number of cholesterol carrying particles and, at a population level, with long term artery disease risk. Higher values are also linked with insulin resistance, an underactive thyroid, and kidney conditions.
What is generally associated with a lower result
Low values are generally viewed as favorable. Very low values are occasionally linked with uncommon inherited patterns of lipoprotein production, but are generally not pursued when the rest of the panel is unremarkable.
Everyday things that move this number
Not every shift in a value reflects disease. These are ordinary factors known to affect this particular measurement:
- Little affected by a recent meal, unlike triglyceride based numbers
- Recent acute illness or inflammation
- Pregnancy
- Recent weight change
- Common medicines, including steroids
Questions to take to your appointment
- Does my ApoB agree with my LDL cholesterol, and what does it mean if they diverge?
- Is ApoB worth tracking alongside or instead of my standard panel?
- Which of my other results does this number add the most information to?
Build a printable questionnaire with your own results →
Where to read more
MedlinePlus, from the US National Library of Medicine, publishes patient-facing pages on individual lab tests and is a reliable next stop: medlineplus.gov/lab-tests .
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