Understanding Lab Tests for Recent Chickenpox infection
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
Chickenpox is a highly contagious viral infection caused by the varicella-zoster virus (VZV). While the characteristic itchy rash typically makes diagnosis straightforward, blood testing can provide definitive confirmation of a recent infection by measuring the body's immune response to the virus.
Recommended Test
Varicella-Zoster Virus (VZV) Antibodies, IgG (Chickenpox)
This test measures IgG antibodies against the varicella-zoster virus in the blood. A significant rise in antibody levels, typically determined through two blood samples taken two weeks apart, indicates a recent chickenpox infection. The increase in antibody concentration demonstrates that the immune system has recently responded to the virus.
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Why Blood Testing for Recent Chickenpox Infection
Blood tests are particularly valuable when clinical symptoms are unclear, when confirming exposure for individuals who may have been in contact with infected persons, or when documentation of recent infection is needed for medical or occupational purposes. These tests detect antibodies that the immune system produces in response to the varicella-zoster virus.
Understanding Test Results
The test works by comparing antibody levels between two samples collected at different times. A four-fold or greater increase in IgG antibody levels between the first and second sample strongly suggests a recent infection. Single samples may show the presence of antibodies but cannot definitively confirm recent infection versus past exposure or vaccination.
Important Considerations
The information here is for educational purposes only and is not a substitute for professional medical advice. Always consult with a healthcare provider for diagnosis and treatment.
