Varicella (chicken pox) and herpes varicella zoster (shingles) are caused by infection with the varicella-zoster virus (VZV). Primary VZV infection is a highly contagious disease characterized by mild skin vesicles and/or rash. VZV affects nearly 4 million children and adults in the United States each year. The Varicella form of the disease produces vesicular pruritic (itchy) lesions. Lesions appear over a period of 2 - 4 days. The disease is most common in children, and symptoms include malaise, sore throat, runny nose, and fever, and can cause more severe and painful illness in adults. Varicella can pose a serious threat to fetuses, neonates, and to non-immune or immunocompromised children and adults.
After primary infection, VZV remains dormant in dorsal root ganglia cells, a type of nerve cell. VZV can become reactivated in the form of zoster (shingles) and generally occurs in older adults whose immunity has waned, the very young, and those with an impaired immune system. A rapid diagnosis is particularly valuable because effective drug therapy is available.
VZV can cause birth defects or post-delivery complications, but is rare. The Varicella-Zoster Virus IgG and IgM test identifies specific components (antibodies) of the immune system that react to the virus. The test is performed on a blood sample drawn from a vein in the patient’s arm. Additional tests may include Rubella antibody, Parvo B19 antibody, and VZV by PCR.
The IgG test is intended for the detection and quantitative determination of antibody to VZV in human serum. Positive results in neonates must be interpreted with caution, because maternal IgG is transferred passively from the mother to the fetus before birth.
IgM assays are generally more useful indicators of infection in children less than 6 months of age. Samples collected very early in the course of an infection (within 5 days after onset of rash) may not have detectable levels of VZV IgG. In such cases, it is recommended that the patient be tested for VZV IgM.
Reference ranges and specimen collection vary from test method and laboratories performing this test. To properly evaluate your test results, consult with the ordering physician or healthcare provider. If you would like to learn more about testing for Varicella-Zoster IgG and IgM click here for further information or you can research one of the references listed below.
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