Herpes Simplex in Emergency Medicine Workup

Updated: Jun 26, 2017
  • Author: Melissa Kohn, MD, MS, FACEP, EMT-T/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)

Monoclonal antibody testing


  • 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