Clinics and Departments

Laboratory Services

Lab Dept:


Test Name:


General Information

Lab Order Codes:



VZV Direct FA; VZV DFA; Herpes Zoster FA; FA for VZV

CPT Codes:

87290 - Infectious agent antigen detection by immunofluorescent technique; Varicella zoster virus

Test Includes:

Detection of Varicella Zoster virus antigen in skin lesions and vesicles, using direct immunofluorescence. Viral culture must be ordered with this test. Refer to Viral Culture


Lab Testing Sections:


Phone Numbers:

MIN Lab: 612-813-5806

STP Lab: 651-220-6555

Test Availability:

Daily, 24 hours

Turnaround Time:

Specimens must arrive by noon for same day results. All specimens received after that time will be held until the next working day for completion

Special Instructions:

Do Not use calcium alginate swabs.
● Requisition must state specific site of specimen and date/time of collection.


Specimen Type:

Swab of vesicular skin lesion


Swab transport system, viral transport media (available in Microbiology)


1 swab, 1 smear


1. Wash vesicles with sterile saline.
Unroof the vesicle and absorb vesicular fluid into a dry swab.
Vigorously scrape base of freshly exposed lesion with swab to obtain cells, which contain virus.
Maintain sterility and forward promptly at ambient temperature.
If specimens cannot be transported to the lab immediately, place swabs in VTM and refrigerate.

Special Processing:

Place swab into viral transport media (VTM). Swabs should remain in VTM for higher yield of cells


Onsite collections: Transport to the laboratory immediately.

Offsite collections: Place swabs in viral transport media and refrigerate. Specimens must be promptly transported to the laboratory, with the next available courier, not to exceed 24 hours from the time of collection. However, delayed transport causes a delay in test results.

Sample Rejection:

Specimen not submitted in appropriate transport container; improperly labeled specimen; insufficient volume; external contamination. If an unacceptable specimen is received, the physician or nursing station will be notified and another specimen will be requested before the specimen is discarded.


Reference Range:

No varicella zoster virus detected by DFA


● A negative result does not eliminate the possibility of varicella zoster virus.
● DFA testing should be performed simultaneously with culture to increase sensitivity.
● Results are collection dependent. Specimen should be collected early in course of disease; specimens collected later rarely yield virus. DFA cannot be interpreted if insufficient cells are present to evaluate


Direct Fluorescent Antibody


Cook, JH, and M Pezzlo (2010) Specimen receipt and accessioning. Section 1. Aerobic bacteriology, 1.2.1-4. In HD Isenberg (ed) Clinical Microbiology Procedures Handbook. American Society for Microbiology, Washington DC

Miller, J Michael (1999) A Guide To Specimen Management in Clinical Microbiology, American Society for Microbiology, Washington DC

Miller, J Michael, and HT Holmes (1999) Specimen Collection, Transport, and Storage In PR Murray et al, (ed), Manual of Clinical Microbiology, 7th edition, American Society for Microbiology, Washington DC, pg 33-104


11/20/2014: Offsite collection information added.

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