Test for Herpes Zoster

Tests are not usually necessary to reach a diagnosis of shingles, a skin and nerve condition caused by the varicella-zoster virus (VZV). However, several tests are available to confirm a diagnosis of shingles.

Features

• The symptoms of shingles, including pain and blistering rash on one side of the body, are usually enough to yield a diagnosis of shingles, according to the Mayo Clinic.

Significance

• Sometimes the symptoms of shingles may be confused with those of another condition or otherwise seem ambiguous. According to the American Academy of Family Physicians (AAFP), testing is done in these cases.

Types

• The AAFP reports that tests used in the diagnosis of shingles include polymerase chain reaction testing (which detects the virus' genetic information), viral culturing and direct immunofluorescent antigen-staining, which indicates an immune reaction against the virus.

Other Tests

• The Tzanck test (or smear), which involves taking a sample scraping from a suspected herpetic sore, can confirm that a herpesvirus (the viral family to which VZV belongs) is present, according to Merck Manuals. However, it cannot identify which virus is causing symptoms.

Considerations

• PCR testing and direct immunofluorescent antigen-staining are considered to be more accurate than viral culturing. However, PCR testing is less widely available than culturing, according to the AAFP.