The Tzanck smear: can dermatologists accurately interpret it?

Abstract

The Tzanck preparation is a standard technique for the rapid diagnosis of herpes simplex and varicella-zoster virus infections. This study was designed to determine the ability of practicing dermatologists to interpret Tzanck preparations accurately. Dermatologists at different levels of training interpreted a series of Tzanck preparations under test conditions. Second- and third-year residents had a pooled average for correct responses of 91%; dermatologists in practice less than 10 years, 84%; dermatologists in practice more than 10 years, 67%. Dermatologists are able to use the Tzanck preparation effectively for diagnosing herpetic infections. Second- and third-year residents who are most likely to be diagnosing blistering eruptions in immunosuppressed or otherwise critically ill patients are especially accurate interpreters.