At a Glance
Why Get Tested?
To diagnose, as necessary, a current, recent, or past case of chickenpox or shingles; to demonstrate immunity to the varicella zoster virus (VZV) or the potential for reactivating a VZV infection prior to receiving immunosuppressive drugs
When to Get Tested?
When you have atypical and/or severe symptoms and your doctor wants to distinguish between a VZV infection and another cause; when a doctor wants to check whether or not you are immune to VZV; sometimes prior to an organ transplant or when a child, pregnant woman, or an immune-compromised person has been exposed to someone with chickenpox
A blood sample drawn from a vein in your arm for VZV antibody testing; to detect the virus itself, a sample of fluid from a blister (vesicle), blood, cerebrospinal fluid, or other body fluid or tissue
Test Preparation Needed?
The Test Sample
What is being tested?
Chickenpox and shingles are caused by an infection with the varicella zoster virus (VZV), a member of the herpes virus family. Varicella zoster virus tests detect either antibodies produced by the immune system in response to a VZV infection or detect the virus itself.
Tests for chickenpox and shingles may be performed to detect and diagnose a current or past infection with VZV. Most often, testing is not necessary to diagnosis an active infection because it can be made from clinical signs and symptoms, but in some people with atypical skin lesions, a diagnostic test helps to confirm the infection. In some people, especially organ transplant recipients and pregnant women, the tests may be used to diagnose a current infection or to determine whether or not they have developed immunity from prior infection or by vaccination.
Before the introduction and widespread use of a chickenpox vaccine in 1995, nearly everyone in the United States became infected by VZV by the time they were an adult. While VZV is present in its latent form in many adults who were infected as children, according to the Centers for Disease Control and Prevention, the incidence of new cases of chickenpox has declined significantly. Two doses of the vaccine are about 98% effective in preventing the infection, and those who do become infected usually have milder symptoms.
Varicella zoster virus can cause chickenpox in the young and in adults who have not been vaccinated or previously exposed. The primary infection is highly contagious, passing from person to person through coughing or sneezing or touching fluid from blisters. In a primary infection, an itchy rash emerges about two weeks after exposure to the virus, followed by the formation of pimple-like papules that become small, fluid-filled blisters (vesicles). The vesicles break, form a crust, and then heal. This process occurs in two or three waves or "crops" of several hundred vesicles over a few days.
Once the initial infection has resolved, the virus becomes latent, persisting in sensory nerve cells. The person develops antibodies during the infection that usually prevent them from getting chickenpox again. However, later in life and in those with weakened immune systems, the virus can reactivate, migrating down the nerve cells to the skin, causing shingles (also known as herpes zoster). Symptoms of shingles include a mild to intense burning or itching pain in a band of skin at the waist, the face, or another location. It is usually in one place on one side of the body but can also occur in multiple locations. Several days after the pain, itching, or tingling begins, a rash, with or without vesicles, forms in the same location. In most people, the rash and pain subside within a few weeks, and the virus again becomes latent. A few may have pain that lingers for several months.
A shingles vaccine is now available for older adults that lowers the risk for having a reactivation of the virus that presents as shingles and lessens the severity of the symptoms if it does occur. In 2006, the Advisory Committee on Immunization Practices (ACIP) began recommending a shingles vaccination for all adults aged 60 years and older. However, the vaccine is not recommended for those who have weakened immune systems.
Most cases of chickenpox and shingles resolve without complications. In people with weakened immune systems, such as those with HIV/AIDS or organ transplant recipients, it can be more severe and long-lasting. In some cases, it may not become latent and may spread to the central nervous system.
In pregnant women, the effects of exposure to VZV on a developing baby or newborn depend on when it occurs and on whether or not the mother has been previously exposed. In the first 20 to 30 weeks of pregnancy, a primary VZV infection may, rarely, cause congenital abnormalities in the unborn baby. If the infection occurs one to three weeks before delivery, the baby may be born with or acquire chickenpox after birth, although the baby may be partially protected by the mother's antibodies. If a newborn is exposed to VZV at birth and does not have maternal antibody protection, then the VZV infection can be fatal.
How is the sample collected for testing?
The sample required depends on whether testing is being done to determine the presence of antibodies or to detect the virus itself and on the health status of the person. Antibody testing requires a blood sample drawn from a vein in the arm. Viral detection may be done on a variety of samples, including a sample of vesicle fluid, blood, cerebrospinal fluid, other body fluid, or tissue.
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.
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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
Kaneshiro, N. (Updated 2011 August 2). Chickenpox. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/001592.htm. Accessed December 2012.
Papadopoulos, A. et. al. (Updated 2011 June 20). Chickenpox. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/1131785-overview through http://emedicine.medscape.com. Accessed December 2012.
Couturier, M. et. al. (Updated 2012 August). Varicella-Zoster Virus - VZV. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/VZV.html?client_ID=LTD through http://www.arupconsult.com. Accessed December 2012.
(© 1995-2012). Varicella-Zoster Virus (VZV) Antibody, IgG and IgM, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/84424 through http://www.mayomedicallaboratories.com. Accessed December 2012.
McPherson, R. and Pincus, M. (© 2011). Henry's Clinical Diagnosis and Management by Laboratory Methods 22nd Edition: Elsevier Saunders, Philadelphia, PA. Pp 1052-1053.
(January 10, 2011) Centers for Disease Control and Prevention. Shingles (Herpes Zoster) Vaccination. Available online at http://www.cdc.gov/shingles/vaccination.html through http://www.cdc.gov. Accessed February 2013.
(May 18, 2012) Centers for Disease Control and Prevention. Shingles (Herpes Zoster) Overview. Available online at http://www.cdc.gov/shingles/index.html through http://www.cdc.gov. Accessed February 2013.
(November 16, 2011) Centers for Disease Control and Prevention. Chickenpox (Varicella). Available online at http://www.cdc.gov/chickenpox/ through http://www.cdc.gov. Accessed February 2013.
Sources Used in Previous Reviews
Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition: Saunders Elsevier, St. Louis, MO. Pp 1623.
Forbes, B. et. al. (© 2007). Bailey & Scott's Diagnostic Microbiology, Twelfth Edition: Mosby Elsevier Press, St. Louis, MO. Pp 748-749.
(Updated 2009 February 3). Shingles: Hope Through Research. National Institute of Neurological Disorders and Stroke [Online information]. Available online at http://www.ninds.nih.gov/disorders/shingles/detail_shingles.htm through http://www.ninds.nih.gov. Accessed February 19, 2009.
(Updated 2009 January 27). Varicella (Chickenpox). CDC, Traveler's Health – Yellow Book, Chapter 4 Prevention of Specific Infectious Diseases [Online information]. Available online at http://wwwn.cdc.gov/travel/yellowBookCh4-Chickenpox.aspx through http://wwwn.cdc.gov. Accessed February 2009.
Rauch, D. (Updated 2007 July 26). Chickenpox. MedlinePlus Medical Encyclopedia [Online information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/001592.htm. Accessed February 2009.
Anderson, W. (Updated 2007 September 14). Varicella-Zoster Virus. eMedicine [Online information]. Available online at http://emedicine.medscape.com/article/231927-overview through http://emedicine.medscape.com. Accessed February 2009.
Miller, G. and Dummer, J. (2007 May 9). Herpes Simplex and Varicella Zoster Viruses: Forgotten but Not Gone. American Journal of Transplant 2007;7(4):741-747. Available online at http://www.medscape.com/viewarticle/556000 through http://www.medscape.com. Accessed February 2009.
(Updated December 2008). Varicella-Zoster Virus – VZV. Arup Consult [Online information]. Available online at http://www.arupconsult.com/Topics/InfectiousDz/Viruses/VZV.html through http://www.arupconsult.com. Accessed February 2009.
Children's Hospital Boston. Varicella Zoster Virus, Congenital Varicella Syndrome. Available online at http://www.childrenshospital.org/az/Site474/mainpageS474P0.html#varicella through http://www.childrenshospital.org. Accessed February 2009.