Apo E Genotyping: Cardiovascular Risk

CPT: 81401
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Special Instructions

This test is intended for evaluation of cardiovascular risk, not for evaluation of those suspected of having Alzheimer's disease.

Expected Turnaround Time

5 - 7 days

Specimen Requirements


Whole blood


5 mL

Minimum Volume

0.5 mL (Note: This volume does not allow for repeat testing.)


Lavender-top (EDTA) tube (preferred) or yellow-top (ACD) tube

Storage Instructions

Maintain specimen at room temperature or refrigerate. Stable at room temperature for eight days.

Causes for Rejection

Clotted whole blood samples (if adequate DNA not obtained); incorrect specimen type; frozen whole blood samples

Test Details


Evaluate individuals with elevated cholesterol and triglycerides for the E2/E2 genotype associated with type III hyperlipoproteinemia. Aid in the diagnosis of hyperlipoproteinemia.


Polymerase chain reaction (PCR) with restriction enzyme digestion and polyacrylamide gel electrophoresis

Additional Information

Type III hyperlipoproteinemia (broad β disease) is a familial dyslipidemia characterized by the combination of elevated serum cholesterol and triglycerides and the presence of the apolipoprotein E (Apo E) genotype E2/E2. Type III hyperlipoproteinemia has an incidence of 1/2,000−1/10,000. This lipid disorder is associated with a high risk of coronary heart disease and peripheral vascular disease. Onset of type III hyperlipoproteinemia is generally in adulthood but varies from late teens to old age. Before vascular disease develops there are usually no symptoms, and most patients with type III hyperlipoproteinemia are identified only from elevated serum cholesterol and triglycerides discovered during a routine screen. Symptoms include angina, heart attack, claudication, and leg pain. In untreated patients, xanthomas (fat deposits) are occasionally seen (flat in palmar creases or tuberous in joints).

The E2 variant of apolipoprotein E is defective in binding to receptors that normally clear harmful lipid particles called B-VLDL from the circulation. One percent of the general population has the E2/E2 genotype, and development of the frank lipid disorder occurs in 1% to 5% of these predisposed individuals, triggered by secondary genetic, hormonal or environmental factors. Ninety-five percent of patients with type III hyperlipoproteinemia are homozygous for E2. Demonstration of the E2/E2 genotype is essential for diagnosis of type III hyperlipoproteinemia.

Distinguishing this disorder from other causes of elevated cholesterol is important because effective treatment of type III hyperlipoproteinemia to prevent atherosclerosis often requires a different approach than treatment of other dyslipidemias.


Eichner AE,Dunn ST,Perveen G, et al. Apolipoprotein E polymorphism and cardiovascular disease: a HuGe review. Am J Epidemiol. 2002; 155(6):487-495. 11882522
Feussner G. Wager A, Kohl B. et al. Clinical features of type III hyperlipoproteinemia: Analysis of 64 patients. Clin Investig. 1993; 71(5):362-366. 8508005
Mahley RW. Huang Y, Rall SC Jr. Pathogenesis of type III hyperlipoproteinemia (dysbetalipoproteinemia): questions, quandaries, and paradoxes. J Lipid Res. 1999; 40(11):1933-1949 10552997
Smelt AHM, de Beer F. Apolipoprotein E and familial dysbetalipoproteinemia: Clinical, biochemical, and genetic aspects. Semin Vasc Med. 2004; 4(3):249-257.15630634


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
503935 Apo E Genotyping: Cardio Risk 503937 APO E Genotyping Result: 21619-2
503935 Apo E Genotyping: Cardio Risk 503936 Methodology: 49549-9
503935 Apo E Genotyping: Cardio Risk 503938 Interpretation: 50398-7
503935 Apo E Genotyping: Cardio Risk 503939 Comment: 77202-0

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