Were you looking instead for APOE genotyping ordered to evaluate for cardiovascular disease? If so, see APOE Genotyping, Cardiovascular Disease.
At a Glance
Why Get Tested?
APOE genotyping is not widely used. The clinical usefulness of this test is still being researched, but it may be used as an aid in the diagnosis of probable late onset Alzheimer disease (AD) in a symptomatic adult
When to Get Tested?
When you have progressive symptoms of dementia and your health practitioner wants to determine the likelihood that this is due to AD
A blood sample drawn from a vein in your arm
Test Preparation Needed?
The Test Sample
What is being tested?
Apolipoprotein (Apo) E is produced under the direction of the APOE gene and is one of five main types of blood lipoproteins (A-E). This test evaluates a person's DNA to determine what combination of APOE forms (genotype) is present. The APOE gene exists in three different forms (alleles) – e2, e3, and e4 – with e3 being the most common allele, found in 60% of the general population. Everyone inherits a pair of APOE genes that is some combination of these three.
APOE e4 has been associated with an increased risk of late onset Alzheimer disease (AD), that is AD that develops after the age of 65. This effect is additive in that one copy of e4 (e2/e4 or e3/e4) carries some increased risk and two copies of e4 (e4/e4) are associated with an even greater risk of developing AD. It is important to note, however, that this risk is only relative. Most individuals with APOE e4 will never develop AD and there are many people with AD who are e4 negative.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
Ask a Laboratory Scientist
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Sources Used in Current Review
Small, G. (Updated 2012 February 8). Alzheimer Disease and APOE-4. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/1787482-overview#showall through http://emedicine.medscape.com. Accessed March 2014.
Anderson, H. (Updated 2014 March 3). Alzheimer Disease. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/1134817-overview through http://emedicine.medscape.com. Accessed March 2014.
(© 2014) What We Know Today About Alzheimer's Disease. Alzheimer’s Association [On-line information]. Available online at http://www.alz.org/research/science/alzheimers_disease_causes.asp#chromosomes through http://www.alz.org. Accessed March 2014.
(2013 January 14). 2011-2012 Alzheimer's Disease Progress Report. Alzheimer's Disease Education and Referral Center [On-line information]. Available online at http://www.nia.nih.gov/alzheimers/publication/2011-2012-alzheimers-disease-progress-report/ through http://www.nia.nih.gov. Accessed March 2014.
(Reviewed 2012 December). Alzheimer's Disease. NIHSeniorHealth [On-line information]. Available online at http://nihseniorhealth.gov/alzheimersdisease/whatisalzheimersdisease/01.html through http://nihseniorhealth.gov. Accessed March 2014.
Sources Used in Previous Reviews
Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].
Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.
Sloane, P. (1998, November 1). Advances in the Treatment of Alzheimer's Disease. American Family Physician by the American Academy of Family Physicians [On-line journal]. Available online at http://www.aafp.org/afp/981101ap/sloane.html through http://www.aafp.org.
Eastman, P. (2002 March). Keeping Alzheimer's at Bay, Early Diagnosis Keeps Patients Functioning Longer. AARP Bulletin Online [On-line serial]. Available online at http://www.aarp.org/bulletin/departments/2002/health/0310_health_1.html through http://www.aarp.org.
McConnell, S., et. al. Unraveling the Mysteries of Alzheimer's Disease: Exciting New Developments in Research. From panel sponsored by the Alzheimer's Association [On-line information]. Available online at http://www.asaging.org/am/cia2/alzheimer.html through http://www.asaging.org.
Galasko, D., et. al. (1998). High Cerebrospinal Fluid Tau and Low Amyloid b42 Levels in the Clinical Diagnosis of Alzheimer Disease and Relation to Apolipoprotein E Genotype. Arch Neurol [On-line journal], vol (55) pages (937-945). Available online at http://archneur.ama-assn.org/issues/v55n7/abs/noc7433.html through http://archneur.ama-assn.org.
ARF (1996-2002). Standard Medical Workup for Alzheimer's Disease. Alzheimer Research Forum [On-line information]. Available online at http://www.alzforum.org/members/research/treatment_guide/workup.html through http://www.alzforum.org.
Family Caregiver Alliance. Fact Sheet: Alzheimer's Disease [On-line information]. Available online at http://www.caregiver.org/factsheets/diagnoses/alzheimersC.html through http://www.caregiver.org.
Bird, T. (2001 June 22 last update). Alzheimer Overview. GeneReviews [On-line information]. Available online through http://www.genetests.org.
Gottlieb, F. and Lambert, J. G. (2002, January 2, last update). Alzheimer’s Disease. MEDLINEplus [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000760.htm.
Miller, M. (1998 February 18). 26 national Alzheimer's Disease Centers Collaborate on Study of the Utility of Genetic Testing for Alzheimer's. National Institutes of Health News Release [On-line press release]. Available online at http://www.nia.nih.gov/news/pr/1998/02%2D18.htm through http://www.nia.nih.gov.
NIH (2000). Progress report on Alzheimer's disease, taking the next steps. NIH Publication No. 00-4859 [On-line report]. Available online at http://www.alzheimers.org/pubs/prog00.htm#Introduction through http://www.alzheimers.org.
UniSci (2002, April 08). New Approaches Seen For Early Alzheimer's Diagnosis. Daily University Science News [On-line Article]. Review of two studies found in Neuropsychology, Vol 16 (2). Available online at http://unisci.com/stories/20022/0408025.htm through http://unisci.com.
Eldercare (2002 February 28, last update). Is it Alzheimer's ... or Just Forgetfulness? Sponsored by Nebraska's Area Agencies on Aging [On-line information]. Available online at http://nncf.unl.edu/eldercare/info/lifeline/LLforget.html through http://nncf.unl.edu.
Hain, T. (2000 February 13). Alzheimer's Disease. Neurology, Northwestern University Medical School [3rd year neurology medical student curriculum material]. Available online at http://www.neuro.nwu.edu/meded/behavioral/alzheimers.html through http://www.neuro.nwu.edu.
Kleiner-Fisman, G., Updated by (2002 January 2, last update). CSF Collection. MEDLINEplus [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003428.htm.
MEDLINEplus, (2001 November 20). Familial dysbetalipoproteinemia. MEDLINEplus [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000402.htm.
Eichner, J., et. al. (2002, March 15). Apolipoprotein E Polymorphism and Cardiovascular Disease. HuGE Review, appeared in Am J Epidemiol 2002 [On-line journal], 155(6): 487-95. Available online at http://www.cdc.gov/genomics/hugenet/reviews/APOEcardio.htm through http://www.cdc.gov.
MEDLINEplus, (2001 October 29). Familial hypercholesterolemia. MEDLINEplus [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000392.htm.
Stephen P. Day, Ph.D. Director, Medical Affairs, Third Wave Molecular Diagnostics.
Robert C. Green, M.D., M.P.H. Professor of Neurology, Genetics and Epidemiology. Director, Alzheimer's Disease Clinical and Research Program. Boston University Schools of Medicine and Public Health, Boston, MA.
Ian R.A. Mackenzie, MD FRCPC. Department of Pathology, Vancouver General Hospital, British Columbia, Canada.
Pagana, K. D. & Pagana, T. J. (© 2007). Mosby's Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 110-114.
(Updated 2009 May 9). Alzheimer's Disease Genetics Fact Sheet. Alzheimer’s Disease Education & Referral Center [On-line information]. Available online at http://www.nia.nih.gov/Alzheimers/Publications/geneticsfs.htm through http://www.nia.nih.gov. Accessed May 2009.
Bird, T. (Revised 2008 July 24). Alzheimer Disease Overview. GeneReviews [On-line information]. Available online at http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene∂=alzheimer through http://www.ncbi.nlm.nih.gov. Accessed May 2009.
Rogaeva, E. (2009 February 5). The Genetic Profile of Alzheimer's Disease: Updates and Considerations. Medscape from Geriatrics and Aging [On-line information]. Available online at http://www.medscape.com/viewarticle/586756 through http://www.medscape.com. Accessed May 2009.
Gandelman, G. (Updated 2008 January 23). Familial dysbetalipoproteinemia. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000402.htm. Accessed May 2009.
Mayo Clinic Staff (2008 September 17). Alzheimer's: Is it in your genes? MayoClinic.com [On-line information]. Available online at http://www.mayoclinic.com/print/alzheimers-genes/AZ00047/METHOD=print through http://www.mayoclinic.com. Accessed May 2009.
(Updated 2008 December). Cardiovascular Disease (Non-traditional Risk Markers) - Risk Markers - CVD (Non-traditional). ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/CardiacDz/CVDRiskMarkerNontrad.html through http://www.arupconsult.com. Accessed May 2009.
(September 18, 2007) Riordan M. Linear association among apoE genotypes with LDL levels and coronary risk. Available online at http://www.theheart.org/article/813529.do through http://www.theheart.org. Accessed July 2009.