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Apolipoprotein E (APOE) Genotyping, Cardiovascular Risk
2013337
Ordering Recommendation

Provides supporting evidence for a diagnosis of type III hyperlipoproteinemia for evaluation of premature coronary heart disease.

Mnemonic
APOE CR
Methodology
Polymerase Chain Reaction/Fluorescence Monitoring
Performed
Mon, Thu
Reported
2-7 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
 
Collect
Lavender (EDTA), Pink (K2EDTA), or Yellow (ACD Solution A or B). 
Specimen Preparation
Transport 3 mL whole blood. (Min: 1 mL) 
Storage/Transport Temperature
Refrigerated. 
Unacceptable Conditions
Plasma or serum. Heparinized specimens. 
Remarks
This test is not recommended for nonsymptomatic patients under 18 years of age. 
Stability
Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month 
Reference Interval
Homozygous APOE e3 (e3/e3): This genotype is the most common (normal) genotype.
Interpretive Data
Background Information for Apolipoprotein E (APOE) Genotyping, Cardiovascular Risk
Characteristics:
Hyperlipoproteinemia III (HPL III) is characterized by increased cholesterol and triglyceride levels, presence of B-VLDL, xanthomas, and premature vascular disease including coronary heart disease (CHD) and peripheral artery disease.
Incidence of HPL III:
Approximately 1 in 5,000.
Inheritance of HPL III:
Multifactorial; greater than 90 percent of affected individuals are homozygous for the e2 allele but other factors such as diabetes and hypothyroidism also play a large role in development of disease.
Penetrance:
1 to 5 percent of individuals homozygous for the e2 will develop HPL III.
Cause:
2 copies of the e2 allele provides supporting evidence for a diagnosis of HPL III in a symptomatic individual but e2 homozygosity is neither necessary nor sufficient for HPL III.
Variants Tested:
APOE gene alleles, e2 (c.388T, p.130Cys and c.526C>T, p.Arg176Cys), e3 (c.388T, p.130Cys and c.526C, p.176Arg ), e4 (c.388T>C, p.Cys130Arg and c.526C, p.176Arg).
Clinical Sensitivity: 90 percent of individuals with HPL III are homozygous for the e2 variant.
Methodology:
Polymerase chain reaction (PCR) and fluorescence monitoring using hybridization probes.
Analytical Sensitivity and Specificity:
99 percent.
Limitations:
Only the e2, e3 and e4 variants will be detected. Rare isoforms of APOE will not be detected. If rare alleles are suspected, phenotyping by isoelectric focusing may be indicated. Diagnostic errors can occur due to rare sequence variations.

This test is performed pursuant to an agreement with Roche Molecular Systems, Inc.

Compliance Statement C: The performance characteristics of this test were validated by ARUP Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test. However, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. ARUP is authorized under Clinical Laboratory Improvement Amendments (CLIA) and by all states to perform high-complexity testing. Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Note
CPT Code(s)
81401
Components
Component Test Code*Component Chart NameLOINC
2013338APOE Specimen
2013339APOE Cardiovascular Risk, Genotype
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • APOE
  • ApoE 2 mutations
  • ApoE cardiac risk
  • ApoLipoprotein E Genotype