Doctors can usually identify shingles when they see an area of rash around the left or right side of your body. If a diagnosis of shingles is not clear, your doctor may order lab tests, most commonly herpes tests, on cells taken from a blister.

If there is reason to think that shingles is present, your doctor may not wait to perform tests before treating you with antiviral medicines. Early treatment may help shorten the length of the illness and prevent complications such as postherpetic neuralgia.