The clinical presentations of varicella or zoster are so characteristic that laboratory confirmation is rarely required. Laboratory diagnosis is required only for atypical presentations, particularly in the immunocompromised.
Virus Isolation - rarely carried out as it requires 2-3 weeks for a results.
Direct detection - electron microscopy may be used for vesicle fluids but cannot distinguish between HSV and VZV. Immunofluorescense on skin scrappings can distinguish between the two.
Serology - the presence of VZV IgG is indicative of past infection and immunity. The presence of IgM is indicative of recent primary infection.