A patient seated in the chair before a blood draw
In person

Apolipoprotein B (ApoB)

A measure of your cholesterol-carrying particles, from one draw.

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  • 2,000+ lab locations. Find one near you
  • Nothing due at the lab. FSA / HSA accepted
  • Ordered by a licensed clinician

At a glance

Collection
Blood draw
A standard blood draw at the lab.
Preparation
None
Nothing to do ahead of time. Water is fine.
Results
1 to 2 days
Typical turnaround after your visit.
Where
2,000+ lab locations
Nationwide, with nothing due at the lab.

About this test

ApoB is a protein found on LDL and related particles that carry cholesterol through your blood, one per particle. Measuring it shows roughly how many of those particles you have, which a cholesterol number alone does not show. It is often read with a standard lipid set. No fasting is needed.

For adults 18 and older. Test availability varies by lab location.

Who should take this test?

This test is for adults who want more detail than a standard cholesterol check, often with a family history of heart disease or a past high cholesterol result.

Ask about this test

Not sure this is the right test?

AI-generated. For information only, not medical advice. Call 911 for an emergency.

What does this test measure?

Your result reflects how many LDL and related particles are in your blood, which can help you and a healthcare provider add detail to a heart risk conversation.

Apolipoprotein B (ApoB)
ApoB is a protein found on LDL, VLDL, and other particles that can carry cholesterol into artery walls. Each of these particles has one ApoB, so the level reflects how many of them are in your blood. In some people, ApoB is raised even when LDL cholesterol is in range.
Why it’s measured: Reflects the number of particles that can carry cholesterol into arteries.

How it works

  1. Step 1

    Order online

    Check out here. A licensed clinician in your state reviews your order and sends it to the lab.

  2. Step 2

    Visit a lab

    Bring a photo ID to any of 2,000+ lab locations. No fasting needed, and nothing is due at the lab.

  3. Step 3

    Get your results

    Results post to your account, usually in 1 to 2 days, each number next to the lab’s reference range.

Find a lab near you

Choose from 2,000+ lab locations nationwide. Your order works at any of them.

What your results tell you

ApoB is reported in milligrams per deciliter (mg/dL) and compared with the lab’s reference range, which is shown on your report.

  • Your number next to the lab’s reference range
  • Explained in plain language
  • A licensed clinician reviews your order and, if appropriate, orders the test.
  • A lab report you can download and share

A healthcare provider reads ApoB with your cholesterol results, blood pressure, and history before suggesting any next step.

Clinical-grade testing, from the comfort of home.

From the lab to your report, every step of our process meets the gold standard in medical testing.

  • CLIA-certified labs

    Every lab we partner with is certified under the Clinical Laboratory Improvement Amendments, meeting both state and federal standards with regular independent inspections.

  • We protect your health data

    We protect your health data with encryption and do not sell it. Some results must be reported to public health authorities by law. See our Privacy Notice.

  • Rigorous quality assurance

    All partner labs run regular internal quality checks, participate in proficiency testing, and comply with federal and state lab regulations.

  • Clinician-reviewed reports

    Results are reviewed by an independent, licensed clinician.

Questions

Common questions.

Anything else, our care team answers by phone, text, or email.

LDL cholesterol measures how much cholesterol is carried inside LDL particles. ApoB reflects how many of those particles there are, because each one carries a single ApoB protein.

The two usually move together, but not in everyone. ApoB can be raised in some people even when LDL cholesterol is within the reference range.

No. ApoB needs no special preparation, so you can test at any time of day, and water is fine. If you add a triglyceride or another fasting test to the same visit, follow the fasting instructions for that test.

People often check ApoB when they want more detail than a standard cholesterol set, when heart disease runs in the family, or when they are following a past high cholesterol result. It is also part of the Heart Health Panel and the Advanced Heart Panel.

ApoB is one input to a heart risk conversation, not a diagnosis. It does not show whether your arteries are narrowed, and it does not replace a look at blood pressure, blood sugar, smoking, and family history. A healthcare provider can explain how your number fits with the rest.

Lab tests are informational and don’t diagnose conditions on their own. Available to adults 18 and older; test availability varies by lab location. A licensed clinician reviews your order and, if appropriate, orders the test. All testing is performed at CLIA-certified laboratories. Not for emergencies: if you think you may be having a medical emergency, call 911.