Your doctor will ask about your symptoms and medical history. A physical exam will be done. Chickenpox is usually diagnosed based on the rash. Blood and laboratory tests to identify the varicella zoster virus (VZV) are available for use in questionable cases, but they are rarely necessary.

Blood and laboratory tests —several tests are available that may help confirm the diagnosis of chickenpox, including:

  • Skin smear to infer the presence of chickenpox virus by staining
  • Skin smear to detect chickenpox viral proteins using immunofluorescence
  • Blood test to detect the presence and measure the amounts of antibodies to chickenpox virus
  • Viral culture