There is a blood test available to check for immunity to the
herpes zoster virus, the virus responsible for
chickenpox. Since 70 to 90 percent of adults who do not remember having chickenpox actually have protection in their blood when tested, chickenpox blood testing before vaccination can be a good cost- saving measure.
Ask your doctor about this chickenpox blood test. If it is not available, it is still safe to receive the vaccine even if you have previously had chickenpox.