Varicella-Zoster Virus DFA with Reflex to Varicella-Zoster Virus Culture
Also known as: VZVFAC
Use
This test is designed to detect the presence of the varicella-zoster virus (VZV) in submitted specimens. Initial testing is done using the Direct Fluorescent Antibody (DFA) method, which is particularly sensitive when utilizing scrapings from the base of lesions. If DFA results are negative or deemed inadequate, a culture is performed to confirm the absence of VZV. The test is useful for identifying cases of varicella (chickenpox) and herpes zoster (shingles), aiding in clinical diagnosis and subsequent management of these conditions.
Special Instructions
The specimen should be collected during the first three days of rash appearance for optimal results. The preferred specimen source includes vesicle fluid or swabs, tissue, or skin scrapings, with collection focused on the base of fresh vesicles to obtain cells. Specimen source should be indicated upon submission.
Limitations
The sensitivity of the DFA method is highly dependent on the specimen quality. A specimen with fewer than 20 cells can lead to a result being reported as inadequate. Additionally, approximately 20% of specimens submitted for this test may be positive for herpes simplex virus, which this test does not include. Disallowed specimen types include bone marrow, CSF, whole blood, and dry or inappropriate swabs.
New York Approved
Methodology
Immunoassay (Immunofluorescent Stain)
Biomarkers
LOINC Codes
- 5882-6
- 31208-2
Result Turnaround Time
3-5 days
Related Documents
For more information, please review the documents below
Specimen
Other
Volume
Not provided
Minimum Volume
Not provided
Collection Instructions
Vesicle fluid or swab, tissue, or skin scrapings. Swab should be rolled in base of fresh vesicle to obtain cells.
Patient Preparation
Collect vesicle specimen during first three days of rash.
Storage Instructions
Immediately transfer specimen to viral transport media and refrigerate.
Causes for Rejection
Bone marrow, CSF, or whole blood; Calcium alginate, eSwab, dry or wood swabs.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | 48 hours |
| Frozen | Unacceptable |