Background: The polymerase chain reaction (PCR) can be used to diagnose a variety of infectious processes.
Objective: We sought to determine whether Tzanck smear debris, vesicle fluid swabs, crusts, or fixed tissue specimens are the best source for template herpes simplex virus (HSV) or varicella-zoster virus (VZV) DNA for the PCR.
Methods: Patients with both clinical and histologic evidence of HSV (n = 6) or VZV (n = 16) infection were examined. Stained Tzanck smears, vesicle fluid swabs, dried crusts, and skin biopsy specimens were obtained at the same time from each patient. DNA was extracted from the different clinical specimens and then examined for HSV or VZV DNA with PCR. Fifteen control subjects did not have clinical or histologic evidence of herpesvirus infection.
Results: In cases of suspected VZV infection, PCR detected VZV DNA sequences from all 15 Tzanck smears, all 15 vesicle swabs, one of one crust, and 14 of 16 fixed tissue specimens. HSV DNA sequences were detected from all six Tzanck smears, all four vesicle fluid swabs, two of two crusts, and five of six fixed tissue specimens.
Conclusion: PCR can detect VZV and HSV DNA sequences from a variety of sources including formalin-fixed tissue specimens. Although viral DNA was detected slightly more frequently from Tzanck smear debris, crusts, and vesicle fluid swabs compared with fixed tissue specimens, each was an excellent source of target DNA for the PCR to confirm the diagnosis of herpesvirus infection.