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Apolipoprotein B and LDL Cholesterol, Serum/Plasma

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

Measures apolipoprotein B and LDL cholesterol in blood to help assess cardiovascular risk related to atherogenic lipoproteins.

Quick summary

["ApoB and LDL cholesterol help estimate the amount of cholesterol-carrying particles that may contribute to artery disease."]

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

Key facts at a glance

LOINC
56036-7
Short code
Apo B/LDLc SerPl
Synonyms
Apo B/LDLc SerPl
Category
lipid
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0
Ref high
100
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
83721
SNOMED
113079007
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 blood test measures apolipoprotein B (ApoB) and low-density lipoprotein (LDL) cholesterol. ApoB estimates the number of cholesterol-carrying particles that can enter artery walls, while LDL cholesterol measures the cholesterol within LDL particles.

Why might I need this test?

A clinician may order this test to help assess cardiovascular risk, particularly when cholesterol results are uncertain or when other risk factors are present. It may also be used to monitor response to cholesterol-lowering treatment or lifestyle changes.

How is the test performed?

A blood sample is collected, and serum or plasma is separated for analysis. ApoB is measured in the laboratory, and LDL cholesterol may be calculated or measured directly, depending on the testing method used by the laboratory.

How do I prepare for the test?

Follow your clinician's preparation instructions. Some laboratories request fasting for lipid testing, while others allow nonfasting samples, so confirm the requirements before your appointment and continue taking medications unless instructed otherwise.

Reference range

Optimal: <100 mg/dLN/A

Specimen: serum

Fasting for 12-14 hours preferred. Water is permitted. Avoid alcohol for 24 hours before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

ApoB and LDL cholesterol

Frequently asked questions

Is ApoB the same as LDL cholesterol?
No. LDL cholesterol measures the amount of cholesterol within LDL particles, while ApoB estimates the total number of atherogenic particles, including LDL and related lipoproteins.
Do I need to fast for this test?
It depends on the laboratory and the reason for testing. Some lipid tests are performed without fasting, but fasting may be requested when results need to be compared with standard reference ranges.
What do high ApoB and LDL cholesterol mean?
They can indicate increased cardiovascular risk from cholesterol-carrying particles. A clinician can interpret the results alongside blood pressure, diabetes status, smoking history, family history, and other findings.
  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