Tzanck test /tsangk/ [Arnault Tzanck, a Russian dermatologist in France, 1886–1954] , a microscopic examination of cellular material from skin lesions to help diagnose certain vesicular diseases. The tissue is scraped from the base of a vesicle, placed on a slide, and stained with Wright’s or Giemsa’s stain. Multinucleated giant cells are diagnostic of herpesvirus or varicella. Typical pemphigus and other cells also can be identified.
