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Cholesterol to Apolipoprotein B Ratio, Serum/Plasma

Published: August 9, 2026Updated: August 16, 2026

This blood test compares total cholesterol with apolipoprotein B (ApoB), a marker of cholesterol-carrying particles that contribute to arterial plaque.

Quick summary

["The result is interpreted alongside ApoB and the full lipid panel to help assess cardiovascular risk."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
48089-7
Short code
Cholest/Apo B SerPl-sRto
Synonyms
Cholest/Apo B SerPl-sRto
Category
lipid
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

This test measures cholesterol and apolipoprotein B (ApoB) in blood and may provide a calculated comparison between them. ApoB estimates the number of atherogenic particles, which can carry cholesterol into artery walls.

Why might I need this test?

A clinician may order it as part of a cardiovascular risk assessment, especially when standard cholesterol results do not fully explain the person's risk. It may be considered for people with high cholesterol, a family history of early heart disease, or other risk factors.

How is the test performed?

A blood sample is collected and analyzed in the laboratory. The reported result compares the measured cholesterol and ApoB values; the calculation method and units are provided by the laboratory.

How do I prepare for the test?

Follow the instructions from the ordering clinician or laboratory. Some lipid tests may be performed without fasting, while others require fasting; if fasting is requested, avoid food and drinks other than water for the period specified by the laboratory.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cholesterol/ApoB ratio

Frequently asked questions

What does apolipoprotein B measure?
ApoB is a protein found on certain cholesterol-carrying lipoproteins. Its blood level helps estimate the number of atherogenic particles that can enter artery walls.
Is a high cholesterol/ApoB ratio dangerous?
A higher result may indicate a greater cholesterol burden relative to the measured ApoB level, but interpretation depends on the complete lipid panel and cardiovascular history. A clinician should explain the result in the context of your overall risk.
Do I need to fast for this test?
Fasting requirements vary by laboratory and the specific test ordered. Follow the instructions provided with the order, because some cholesterol and ApoB measurements can be performed without fasting.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy