Chickenpox and Shingles Tests

Other names: Herpes Zoster; Varicella Zoster Virus (VZV); Varicella Zoster Virus by PCR; Varicella Zoster Virus Culture; IgC and IgM; Varicella Zoster Virus Antibodies; Varicella Zoster Virus by DFA

The chicken pox and shingles test is used to diagnose patients with illnesses in the event that they display atypical symptoms and the doctor cannot diagnose them by physical examination alone. Chicken pox and shingles are caused by the varicella zoster virus; the virus is very common and can be passed from person to person very quickly.

When is the test used?

The test is usually used to confirm a diagnosis of chicken pox or shingles when the patient has atypical symptoms; in most cases, doctors can diagnose the conditions based on a physical examination because they produce distinctive skin rashes; however, this is not always the case and a blood test may be required.

The test may also be ordered for pregnant women, people with HIV or AIDS, patients who are about to undergo transplant surgery and newborn babies (who have been exposed to the VZV infection) to check immunity to the VZV virus.

How is the test done?

Antibody testing is done using a blood sample; the sample is taken from a vein in the arm using a needle and then it is bottled, labelled and sent away to the laboratory for analysis.

If the test is being carried out to test for the presence of the virus, several different tests may be carried out. Samples of blood, vesicle fluid, tissue or cerebrospinal fluid may be taken and analysed.

What does the test result mean?

It is sometimes difficult to interpret the test results when they are being used to differentiate between a latent and an active infection because a person who has been infected by a VZV infection will continue to have the virus in their body after their symptoms have disappeared. It is also difficult to test newborns because their immune systems are not fully developed and consequently they may not have a strong antibody response to the infection.

If the patient tests positive for the varicella zoster virus and they have symptoms, it is likely that they have an active infection. If they test positive but levels are relatively low and they do not have symptoms, this usually indicates that they have a non-symptomatic condition.

If the test has been used to detect antibodies and both VZV IgG and IgM are detected, this usually indicates that the person has been exposed to the varicella zoster virus and has chicken pox; it may also mean that the infection has recurred and the patient has shingles. If the test reveals only IgM antibodies, this may indicate that the baby has a congenital VZV infection.

Specific Blood Tests

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