Tzanck test

In dermatopathology, the Tzanck test, also Tzanck smear, is scraping of an ulcer base to look for Tzanck cells. It is sometimes also called the chickenpox skin test and the herpes skin test.

Tzanck cells (multinucleated giant cells) are found in:

The Tzanck test has been largely replaced by DFA for identification of the herpes virus

A modified test can be performed using proprietary agents which requires fewer steps and allows the sample to be fixed quicker.

It is named after Arnault Tzanck (1886–1954), a French dermatologist.

...
Wikipedia