Quest AD-Detect® Apolipoprotein E (ApoE) Isoform, Plasma

What this laboratory test evaluates

Details
Apolipoprotein E (ApoE) is a well-defined genetic risk factor for late-onset Alzheimer's disease (AD). The human APOE gene has three polymorphic alleles, E2, E3 and E4 that result in six different genotypes: E2/E2, E2/E3, E3/E3, E2/ E4, E3/E4 and E4/E4. About half of AD patients carry the E4 allele (compared with 14% in the general population), with the majority being heterozygotes (E3/E4). The number of inherited E4 alleles is associated with both increased disease risk and decreased average age of onset compared with inheritance of the E2 or E3 alleles. The differences between the three ApoE isoforms are based on two amino acids that affect its structure and hence the interaction and binding of the protein with various lipids and beta-amyloid (AB). ApoE and AB can co-localize in the brain, and therefore their complementary roles in AD have been studied extensively. Circulating plasma and CSF ApoE levels were recently found to be potential biomarkers for AD.

Test ResourcesTest FAQ: Quest Dementia Testing

Additional test information

Apolipoprotein E (ApoE) is a well-defined genetic risk factor for late-onset Alzheimer's disease (AD). The human APOE gene has three polymorphic alleles, E2, E3 and E4 that result in six different genotypes: E2/E2, E2/E3, E3/E3, E2/ E4, E3/E4 and E4/E4. About half of AD patients carry the E4 allele (compared with 14% in the general population), with the majority being heterozygotes (E3/E4). The number of inherited E4 alleles is associated with both increased disease risk and decreased average age of onset compared with inheritance of the E2 or E3 alleles. The differences between the three ApoE isoforms are based on two amino acids that affect its structure and hence the interaction and binding of the protein with various lipids and beta-amyloid (AB). ApoE and AB can co-localize in the brain, and therefore their complementary roles in AD have been studied extensively. Circulating plasma and CSF ApoE levels were recently found to be potential biomarkers for AD.

Collection and processing

• Sample type: Plasma
• Fasting: No
• Estimated laboratory processing: Results should be available in 2 – 5 business days after the sample is collected

How Sunridge uses laboratory information

Sunridge considers the medical question, symptoms, history, medications, prior results, and whether the finding could change care before recommending testing. A laboratory result is not interpreted in isolation and does not establish a diagnosis by itself.

Before requesting this test

Availability, collection requirements, eligibility, and processing estimates can change. Sunridge reviews each request and, when appropriate, creates the order through Fullscript. Follow the current instructions supplied with the approved order.