The Tzanck smear: can dermatologists accurately interpret it?

J Am Acad Dermatol. 1992 Sep;27(3):403-5. doi: 10.1016/0190-9622(92)70207-v.


Background: The Tzanck preparation is a standard technique for the rapid diagnosis of herpes simplex and varicella-zoster virus infections.

Objective: This study was designed to determine the ability of practicing dermatologists to interpret Tzanck preparations accurately.

Methods: Dermatologists at different levels of training interpreted a series of Tzanck preparations under test conditions.

Results: 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%.

Conclusion: 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.

MeSH terms

  • Clinical Competence*
  • Dermatology / education
  • Herpes Simplex / diagnosis*
  • Herpes Simplex / pathology
  • Herpes Zoster / diagnosis*
  • Herpes Zoster / pathology
  • Histocytological Preparation Techniques*
  • Humans
  • Internship and Residency
  • Time Factors