Apolipoprotein E (APOE) Genotyping, Cardiovascular Risk
Test Mnemonic
APOEG
CPT Codes
- 81401 - QTY (1)
LOINC ®
21619-2
Aliases
- Apolipoprotein E (Condon 112 &158)
Performing Laboratory
ARUP
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 3 mL | Whole blood | EDTA (Lavender) | Refrigerated |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 3 mL | Whole blood | ACD A or B (Yellow) | Refrigerated |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL |
Stability
| Environmental Condition | Description |
|---|---|
| Refrigerated | 1 week |
| Frozen | 1 month |
| Ambient | 72 hours |
Days Performed
Mon, Thu
Turnaround Time
3 - 8 days
Methodology
| Name | Description |
|---|---|
| Fluorescence Monitoring | |
| Polymerase Chain Reaction (PCR) |
Reference Range
Special Info
This test is not recommended for nonsymptomatic patients under 18 years of age. Plasma, serum and frozen specimens in glass collection tubes will be rejected. This test is New York DOH approved.
Clinical Info
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.