Herpes Simplex Virus (HSV) in Emergency Medicine Workup

Updated: Jul 16, 2019
  • Author: Melissa Kohn, MD, MS, FACEP, EMT-PHP; Chief Editor: Steven C Dronen, MD, FAAEM  more...
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Laboratory Studies

Scrapings from suspected lesions of herpes simplex (Tzanck smear). This is not a reliable screening test, with a reported sensitivity of 65%. It also does not identify the type of herpes simplex virus (HSV) present.

  • Multinucleated giant cells, as shown in the image below

    Tzanck smear showing a multinucleated giant cell. Tzanck smear showing a multinucleated giant cell.
  • Intranuclear inclusions

Viral culture from skin vesicles (more sensitive that Tzanck smear but dependent on duration of viral shedding); consider the following:

  • Preferably from vesicular lesions within 3 days of appearance
  • The earlier the sample is taken, the more accurate the results

Monoclonal antibody testing; consider the following:

  • Primarily used when other methods cannot be used (ie, no active lesions to swab)
  • Also used when other methods yielded negative results but there is still significant concern for infection [13]


  • HSV IgG detection via ELISA or Western blot

Cerebrospinal fluid (CSF) analysis for lymphocytic pleocytosis

  • Bloody CSF

  • Polymerase chain reaction (PCR) detects HSV DNA


Imaging Studies

CT scan and MRI for differentiation of encephalitis from other entities



Slit-lamp examination for dendritic keratitis with ocular involvement

Lumbar puncture, if concerned about encephalitis

Brain biopsy, if encephalitis is considered