Tzanck test

Definition

The Tzanck test is a method of testing sores for the herpes simplex virus (which causes cold sores, fever blister, or genital sores), or varicella-zoster virus (which causes chickenpox and "shingles").

How the test is performed

The sore is scraped and the scraping is put on a slide and stained. The health care provider then examines it under a microscope.

How to prepare for the test

There is no special preparation necessary.

How the test will feel

When the sore is scraped or rubbed, there may be mild discomfort.

Why the test is performed

The test may help diagnose or confirm an infection with one of these two viruses. This test cannot distinguish between these two viruses.

Normal Values

No presence of herpes-infected cells in the scraping is normal.

What abnormal results mean

The results are immediately available. If herpes-infected cells are detected, the patient has been infected with one or the other of the following:

• Herpes simplex (which causes cold sores, fever blister, or genital sores)
• Varicella-zoster virus (which causes chickenpox and "shingles").

What the risks are

There are no risks with this test.

Special considerations

There is a high rate of false-negative results even when the virus is present.

Illustrations

Viral lesion culture

Page Content:

Herpes skin test; Chicken pox skin test