Special Precautions/Comments:

Interferences: Interference may be encountered with certain sera containing antibodies directed against reagent components. For this reason, assay results should be interpreted taking into consideration the patient’s medical history and the results of any other tests performed.

Method: Enzyme-Linked Fluorescent Assay (ELFA). Calibration: VIDAS assay kit standard. EQA scheme: NEQAS.  IQC: VIDAS commercial preparations.

Interpretation: Results are reported as NOT detected, Equivocal, or DETECTED. Positive samples may also be noted as “consistent with past chicken pox” or “presumably maternal in origin“, this is dependant on provided clinical details. For samples from pregnant women or immunocompromised patients who have been in contact with chickenpox, Equivocal or Negative samples may be referred to Newcastle Hospitals Virology Service for confirmatory testing using an alternative method.

Additional Information:

Background information:  Varicella (chickenpox) and zoster (shingles) are two different clinical manifestations of infection with the varicella-zoster virus (VZV). Chickenpox, the primary infection, is a highly contagious disease which spreads rapidly in susceptible populations (e.g. children or immunocompromised adults). It is spread by direct contact or by airborne droplets. The contagious period is from 24 hours before until six or seven days after the appearance of vesicles. In most cases, chickenpox is a mild illness occurring in childhood, characterised by a mild fever and malaise accompanied by a vesicular rash. However, adults with chickenpox usually have a high fever and severe constitutional symptoms. Approximately 20% develop pneumonia. Shingles generally occurs in adults, resulting from a reactivation of latent VZV. Although there is often no apparent reason for zoster to occur, it often is linked to stress, trauma, or certain types of drug therapy.