What diagnostic test is used for varicella?

The Tzanck smear is a diagnostic test that is traditionally used to identify infections caused by herpes viruses, including varicella-zoster virus (VZV), which is responsible for chickenpox (varicella). In this test, a scraping is made from a vesicle (blister) that has developed due to the viral infection. The sample is then stained and analyzed under a microscope to detect any multinucleated giant cells, which are indicative of herpes virus infections. While the Tzanck smear is not the most specific or sensitive test for varicella, it provides rapid results and can be used in clinical settings for preliminary diagnosis.

Other tests such as ELISA and Western blot are more specific and sensitive for diagnosing varicella but are less commonly used in acute settings because they typically require more time for processing and results. ELISA detects specific antibodies against pathogens, and Western blot is used for more detailed serological typing. The rapid strep test, on the other hand, is specifically designed to diagnose streptococcal infections and is not relevant for evaluating varicella. Thus, the Tzanck smear remains a notable option for diagnosing chickenpox in appropriate clinical contexts.