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Test Code LAB4884 Varicella-Zoster Virus (VZV) DNA Detection by PCR

Methodology

Polymerase Chain Reaction (PCR)

Performing Laboratory

Barnes-Jewish Hospital Molecular Infectious Disease Laboratory – whole blood, swab, CSF

 

Mayo Clinical Laboratory –fresh biopsy or tissue

Specimen Requirements

Acceptable Specimens:

Whole blood (lavender-top/EDTA tube), Swab in viral transport medium,  CSF, fresh biopsy or tissue
 

Collection Procedure:

Blood

1. Draw blood into lavender-top/EDTA tube. Avoid hemolysis.

2. Maintain sterility and forward promptly at ambient temperature only.

For BJH Patients: Laboratory medicine resident review and approval is required for blood specimen requests.

 

Swab

1. Obtain a vial of universal/viral transport medium (UTM) with collection swab

2. Collect specimen

3. Place the swab in labeled UTM vial, break off shaft of swab and discard excess piece of shaft. To prevent leaking, make sure the swabs do not interfere with tightening cap on vial.

 

Note:

1. Specimen source is required

 

CSF
1. Aseptically collect ≥1 mL of CSF.

2. Place in a leak-proof screw-capped, sterile container.

3. Maintain sterility and forward promptly.

4. If transport is delayed, refrigerate specimen.

For BJH Patients: Laboratory medicine resident review and approval is required for CSF specimen requests.

 

Biopsy/Tissue

1. Aseptically collect 2x2mm of tissue.

2. Place in a leak-proof screw-capped, sterile container with 1-2 mL of sterile saline.

3. Maintain sterility and forward promptly.

4. If transport is delayed, refrigerate specimen.

Note: Specimen source is required

Specimen Requirements Additional Information

Ambient/Refrigerate/Frozen OK for all specimen types

 

Refrigerated specimens must be tested within 7 days
Frozen specimens must be tested within 30 days

Reference Values

Negative

Day(s) Test Set Up

Monday through Sunday (MID)

Monday through Saturday (Mayo)

Turnaround Time:

Routine: 1- 3 days (BJH MID)

                2 – 4 days (Mayo)

Test Classification and CPT Coding

Test Classification:

BJH MID assay is FDA cleared for performance on lesion swabs and CSF and has also been evaluated by the Barnes Jewish Molecular Infectious Disease Laboratory for performance on whole blood.

 

The Mayo test was developed and performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

 

Assay Limit of Detection:

Whole Blood:  500 copies/mL

CSF: 1,500 copies/mL

Swabs:  3,500 copies/mL

Tissue: 10-20 copies/mL

Limitations:

-The detection of viral nucleic acid is dependent upon proper sample collection, transport, handling and storage. Failure to observe proper procedures in any one of these steps can lead to incorrect results.

-False-negative results may occur if the viruses are present at a level that is below the analytical sensitivity of the assay or if the virus has genomic mutations, insertions, deletions, or rearrangements or if performed very early in the course of illness.

-Most adults have been exposed to VZV at some point during their lifetime and can transiently have detectable virus from different sample types with or without symptomatology.  Positive results should be interpreted in the appropriate clinical context.

 

CPT Code:

87798

Additional Information

For BJH Laboratory Use Only

Minimum Volume:

Blood: 1 mL of EDTA
CSF: 0.5 mL

Laboratory Processing Instructions:
BJH Microbiology will forward tissue to Mayo Clinic Laboratory.