Fast Five Quiz: How Much Do You Know About Shingles?

William James, MD; Camila K. Janniger, MD

Disclosures

March 09, 2017

Although VZV can be cultured, its growth rate is usually too slow for culturing to make a timely contribution to diagnosis. One of the least expensive and simplest laboratory diagnostic methods for VZV and other herpesviruses is the Tzanck smear. The Tzanck smear is performed by obtaining a scraping from the base of a fresh vesicular lesion after it has been unroofed, spreading and drying the collected material on a glass slide, staining the result with Giemsa, and examining the material with a microscope for the characteristic presence of multinucleated giant cells.

The Tzanck smear confirms that the lesion is herpetic, but it cannot differentiate between VZV and other herpesviruses. Furthermore, this test has limited sensitivity compared with other diagnostic methods, such as PCR assay. Thus, when acute diagnostic confirmation is desired, modern tests, such as direct fluorescent antibody (DFA) testing or PCR (if available), are preferred to the Tzanck smear.

For more on the workup of herpes zoster, read here.

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