Skip to content

Apolipoprotein E Allele Testing (E4/E3 Ratio or Specific Allele Identification)

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

This test checks the genetic variation of apolipoprotein E (ApoE), a protein involved in lipid metabolism. It may be used to assess risk for certain cardiovascular or neurodegenerative conditions.

Quick summary

["Understanding your ApoE genetic profile can help inform your risk for heart disease or Alzheimer’s disease."]

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

Key facts at a glance

LOINC
34733-6
Short code
Deprecated APOE allele3 Bld/T
Synonyms
Deprecated APOE allele3 Bld/T
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
molgen
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have a family history of conditions like Alzheimer’s disease, heart disease, or stroke. It could also be part of a genetic screening or evaluation for certain genetic disorders.

What the Test Measures

The test identifies specific alleles (versions) of the ApoE gene, often focusing on the E2, E3, and E4 variants. ApoE variants influence how your body processes fats and cholesterol, which can affect heart health and risk of diseases like Alzheimer’s.

Sample Collection and Preparation

A blood sample is typically taken from a vein in your arm. This test does not require fasting unless specified by your provider. The sample is processed to analyze genetic material.

What the Results Mean

Results show the presence of specific ApoE alleles (e.g., E4/E3 ratio or specific allele types). The interpretation depends on your clinical context and family history. For example, having the E4 allele is associated with a higher risk of Alzheimer’s disease.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

None

Frequently asked questions

What does an ApoE allele test tell me about my health?
It identifies specific genetic variations of ApoE, which can influence your risk for conditions like Alzheimer’s disease or cardiovascular disease. Results help your healthcare provider assess risks and guide personalized care plans.
How is this test different from a cholesterol test?
A cholesterol test measures fat levels in your blood, while this test examines genetic variations (alleles) of ApoE, which affect how your body processes fats and cholesterol over time. Both can provide insights into heart health, but they measure different aspects.
Do I need to fast for this test?
No fasting is usually required unless your provider specifies otherwise. Blood is drawn from a vein, and the sample is analyzed for genetic material related to ApoE alleles.
  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