The Tzanck smear test: rediscovery of a practical diagnostic tool.

The Tzanck smear test is a simple, rapid, valuable, and cost-effective diagnostic method based on the investigation of characteristics of individual cells. In this method, materials are obtained by various techniques and then transferred to a glass slide. Slides can be stained with various dyes and then are examined under a light microscope. To date, cytology has mostly been used in the diagnosis of various erosive-vesiculobullous and nodular lesions, including many tumors. The sampling methods for Tzanck smears and the cytologic findings of a broad range of skin diseases that could provide a rapid diagnosis are described.