What are the other Names for this Test? (Equivalent Terms)
- Herpes Zoster Test
- Postherpatic Neuralgia Test
- Varicella Zoster Virus (VZV) Test
What is Chickenpox and Shingles Test? (Background Information)
- Chickenpox and Shingles Test may be performed to detect and diagnose a current or past chickenpox and/or shingles (herpes zoster) infection. The infections are caused by the Varicella Zoster Virus (VZV)
- Many a times, Chickenpox and Shingles diagnosis is simply made based on the clinical signs and symptoms. However in some cases, individuals may not have the typical presentations of the disease. Under such circumstances, the diagnosis is confirmed by the test
- The test may also be used on pregnant women or the recipient of an organ transplant, to assess their immunity towards the infection, either due to a past infection or vaccination. This helps the healthcare provider advice the individual appropriately, on following necessary precautions
Two main methods are used to test for infection:
- Antibody testing: IgM and IgG antibody, produced by the body in response to infection by the virus, are tested in the blood. Presence of these antibodies help verify recent or past infection by the virus
- Detection of the VZV virus: This is done through tests such as viral DNA analysis, viral cultures, and direct fluorescent antibody testing. Blood or body fluids are tested to detect presence of the virus
What are the Clinical Indications for performing the Chickenpox and Shingles Test?
The healthcare provider may order Chickenpox and Shingles Test in the following cases:
- To determine current or past infections
- To determine immunity to the virus, either due to a past infection or vaccination
- To diagnose current infection in an individual not present with typical signs and symptoms of the viral infection
Individuals in the following category should also get tested:
- Pregnant women
- Immune-compromised individuals, who are exposed to VZV
- Organ transplant recipients
How is the Specimen Collected for Chickenpox and Shingles Test?
Sample required: Blood for VZV antibody testing; body fluids to detect the virus
Process: Insertion of needle into a vein (arm) to obtain blood sample. Fluid is collected from a blister, cerebrospinal fluid, or other body fluids
Preparation required: None
What is the Significance of the Chickenpox and Shingles Test Result?
The significance of Chickenpox and Shingles Test results are explained below:
Presence of both IgG and IgM:
- In a symptomatic individual, this indicates that either the person is infected with chickenpox for the first time, or the individual has shingles as a result of VZV infection being reactivated
Presence of IgM:
- It is an indication that the infection is very recent
- In newborns, it is an indication that the child has congenital VZV infection
Sometimes, an individual showing typical signs and symptoms may have low or undetectable levels of IgG and/or IgM. This is an indication that the person may either have a condition other than VZV, or that the individual’s immunity is compromised. The immune system may not be responding normally, and is thus unable to produce enough antibodies to fight the infection.
Detection of VZV virus through viral cultures, viral DNA analysis, or direct fluorescent antibody tests, confirms the presence of infection. However, a negative test result may either be due to the absence of or the presence of low numbers, of the viral particles in the sample. Thus, a negative test result may not indicate an absence of infection.
The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.
Additional and Relevant Useful Information:
- Chickenpox is a highly contagious viral infection marked by red rashes on the body. It is caused by primary infection with Varicella Zoster Virus (VZV), also called Herpes Zoster Virus
- This infection usually causes mild illness and commonly occurs in children
- The symptoms are aching muscles, headache, loss of appetite, and nausea, followed by rashes and/or oral sores, and a low-grade fever. These symptoms usually lasts for about 2 weeks and most people recover without any complications
- In case the infection occurs in adults and immunosuppressed people, it may cause a more severe illness having complications such as pneumonia, encephalitis, even resulting in death
Shingles (or Herpes Zoster):
- Shingles is a viral disease marked by red, painful rashes with blisters
- It is caused due to reactivation of chickenpox virus acquired during childhood, in people whose immunity has decreased; either due to old age, or any chronic illnesses
- The virus stays as latent infection in the nerve cells after the chickenpox infection has resolved and may be reactivated, if the body immunity gets lowered
- Shingles may also be acquired as fresh infection from infected people, by those having a weak immune system. This infection commonly occurs in older adults
- The symptoms are fever, headache, and general discomfort followed by itching, burning pain, oversensitivity, and paresthesias (tickling, burning sensation)
IgM & IgG antibodies:
- Both are antibodies belonging to a class of proteins called Immunoglobulin (Ig)
- While IgM (short-term) is produced immediately when the virus attacks the body, IgG (life-long) is produced much later
- Thus, the presence (or absence) of these antibodies gives an indication of the duration of infection
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.