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Infectious agent antigen detection by immunofluorescent technique; Varicella zoster virus

CPT4 code

Name of the Procedure:

Infectious Agent Antigen Detection by Immunofluorescent Technique - Varicella Zoster Virus (IFAT for VZV).


This test detects the presence of antigens from the Varicella Zoster Virus (VZV), which causes chickenpox and shingles, using a specialized technique involving fluorescent dyes that bind to viral antigens in a sample.


The purpose of this test is to diagnose infections caused by VZV. It helps confirm whether a patient has chickenpox or shingles, which are both caused by the same virus. This information is crucial for proper treatment and management of the infection.


  • Rash or skin lesions that resemble chickenpox or shingles.
  • Symptoms such as fever, headache, tiredness, or a painful skin rash.
  • Immune-compromised patients with unexplained rashes or suspected VZV infection.
  • Monitoring of VZV in pregnant women exposed to the virus.


  • Patients typically do not require any special preparation.
  • Inform the healthcare provider of any medications or supplements being taken.

Procedure Description

  1. A sample, often a skin swab or fluid from a blister, is collected.
  2. The sample is placed on a slide.
  3. Fluorescent-labeled antibodies designed to bind specifically to VZV antigens are applied.
  4. The slide is examined under a fluorescence microscope.
  5. If VZV antigens are present, they will glow under the microscope.

Tools: Fluorescence microscope, immunofluorescent dyes, collection swabs.

Anesthesia: Not required.


The procedure itself takes approximately 15-30 minutes, but results typically take a few hours to a few days, depending on the lab's processing times.


This test is usually performed in a hospital laboratory or specialized diagnostic lab.


  • Laboratory technicians or technologists specially trained in immunofluorescence techniques.
  • Pathologists or microbiologists may interpret the results.

Risks and Complications

  • There is minimal risk associated since the procedure is non-invasive.
  • Rarely, there may be minor discomfort or irritation at the sample collection site.


  • Accurate and rapid diagnosis of VZV infection, allowing for timely treatment.
  • Helps avoid unnecessary treatments if the patient's condition is due to another cause.


  • No recovery time is needed as the procedure is non-invasive.
  • Patients can resume normal activities immediately after sample collection.


  • Polymerase Chain Reaction (PCR) testing which is highly sensitive and specific for VZV DNA.
  • Serological tests to detect antibodies developed in response to VZV.

Pros and Cons:

  • IFAT is rapid and provides visual confirmation but may be less sensitive than PCR.
  • PCR is highly sensitive but more expensive and requires specialized equipment.

Patient Experience

  • Patients may experience slight discomfort during sample collection.
  • Generally, the procedure is well-tolerated and quick.
  • Results interpretation and treatment decisions will follow once results are available.

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