The Anti-Varicella Zoster Antibody IgM (Varicella IgM) test detects IgM antibodies to the Varicella-Zoster Virus (VZV), indicating a recent or acute infection with chickenpox (varicella) or shingles (herpes zoster), as IgM is the first antibody produced. This blood test helps doctors confirm active disease, differentiate it from past immunity, guide treatment, and is crucial for high-risk groups like pregnant women or immunocompromised individuals with symptoms like fever or rash. No fasting is needed, but recent vaccinations or medications should be mentioned to your doctor