OverviewLaboratory testing can be useful, particularly in cases with less typical clinical presentations.Testing is recommended to:Confirm suspected cases of varicella.Confirm varicella as the cause of outbreaks.Confirm varicella in severe cases (hospitalizations or deaths) or unusual cases.Determine susceptibility to varicella.Determine if suspected vaccine-related adverse events were caused by vaccine-strain VZV.Resource labCDC Herpesvirus Laboratory:The CDC Herpesvirus Laboratory can provide several types of VZV-specific testing free-of-charge to state and local public health departments who require confirmatory evidence for VZV infection or confirmation of atypical herpes zoster cases. The laboratory also conducts free testing for physicians and scientists participating in various epidemiologic and laboratory-based studies.Specimens can also be submitted for suspected vaccine-related adverse events, including:Rash occurring 7 to 42 days after vaccinationSuspected secondary transmis...