TZANCK SMEAR MICROSCOPIC EXAMINATION

What this test checks

A rapid bedside test where cells are scraped from a blister or skin sore and examined under the microscope. Used primarily to diagnose herpes simplex (cold sores, genital herpes) and herpes zoster (shingles).

Why do people get this test?

The Tzanck smear provides a quick answer when blistering skin disease is suspected — particularly herpes infections. A positive result allows antiviral treatment to start immediately, shortening the illness.

When you should consider this test

• When herpes simplex or herpes zoster (shingles) is suspected
• When a blister or vesicular rash needs rapid confirmation
• When prompt antiviral treatment depends on a quick diagnosis

How to prepare

No preparation needed. The test involves a gentle scraping from the base of a blister — mildly uncomfortable but very quick.