Herpes Simplex and Varicella Zoster Viruses

Laboratory Diagnosis

December 2009

There are several laboratory testing options for HSV and VZV. A quick and simple method is the Tzanck smear, in which scrapings of cells from the base of an unroofed blister are placed on a glass slide and stained with Giemsa or papanicolaou stain. The microscopist then looks for the presence of virally- infected cells, which classically, as shown here, are multinucleated, and have glassy nuclear contents, marginalized nuclear chromatin, and nuclear molding. This presentation is diagnostic for HSV and VZV herpes viruses, but it cannot distinguish between the 2 of them.

In order to actually differentiate HSV and VZV, alternative methods such as viral culture or PCR must be used. PCR includes both conventional and real-time methods, and it is the fastest, most sensitive method for detection of both viruses. So, given these advantages, real-time PCR is the only method used at Mayo Clinic for diagnosis of HSV or VZV from anogenital and dermal specimens, which are the most common specimens that we receive for these viruses.

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Laboratory Diagnosis

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Jump to section:

• Introduction
• The Viruses
• Laboratory Diagnosis
• HSV/VZV Real-time PCR Sample Workflow
• Is Extraction Required for Dermal and Anogenital Specimens?
• Direct Processing in Neutralization Buffer: An Alternative to MagNA Pure Extraction
• Match Up Identifying Information
• Remove Swab from the Culturette Tube
• Heat Swab in Neutralization Buffer
• Sample is Ready for PCR
• A New Workflow for Dermal and Anogenital Swabs
• Direct Processing in Neutralization Buffer: Comparable to DNA Extraction?
• Comparison of Detection - HSV
• Results: Comparison of Amplification Cycle Threshold
• Comparison of Detection - VZV
• Results: Comparison of Amplification Crossing Points
• Questions and Answers
• Questions and Answers
• M5 Media vs Culturette Tubes: Experiment
• M5 Media vs Culturette Tubes: Results
• Conclusions
• Questions?