Tests and diagnosis. Shingles is usually diagnosed based on the history of pain on one side of your body, along with the telltale rash and blisters. Your doctor may also take a tissue scraping or culture of the blisters for examination in the laboratory. 1  Preparing for your appointment.2  Treatments and drugs.hingles is usually diagnosed based on the history of pain on one side of your body, along with the telltale rash and blisters. Your doctor may also take a tissue scraping or culture of the blisters for examination in the laboratory. 1  Preparing for your appointment. 2  Treatments and drugs.