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Lab Manual for Moffitt-Long and Mount Zion

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Varicella-zoster Antigen (DFA)

Item Value
Approval req'd? No
Available Stat? No
Utilization Guidelines Vessicular skin lesion suspected of being varicella (Chicken Pox) or zoster (shingles) should be diagnosed by immunofluorescent assay rather than culture.
Test code P346
Test group Varicella-zoster
Performed by Microbiology
In House Availability Monday-Friday, day and evening shifts. Weekends day shift only.
Method Direct immunofluorescent assay
Collection Instructions Each slide should contain two spots of cells obtained from the base of an intact vesicle with a scalpel blade or swab. These spots should be approximately 1.5 cm in diameter (the size of a dime)
Container type Glass slide x2 for smears, viral holding medium for tissue biopsies.
Sample type Unfixed tissue biopsy or smear of cells from vesicle base (see collection instructions)
Preferred volume
Smear Two slides, each with two cell spots.
Tissue biopsy 1 gm
Min. Volume
Smear One slide with two spots or two slides each with one spot
Tissue biopsy 0.5 gm
UCSF Rejection Criteria Improperly collected sample. Unsuitable sample types.
Processing notes Prepare two touch prep smears from tissue biopsy.

Note: Do not reject samples submitted on swabs in holding media
Normal range Negative
Critical value Positive DFA from inpatient or ED Patient.
Synonyms VZ; VZV; VZV Ag; VZV antigen; Varicella-zoster Ag; Varicella-zoster antigen
Stability Slides once prepared are stable at room temperature for 24 hours. For more prolonged stability, fix smears in acetone and freeze them at -70C.
Turn around times Same or next day
Additional information DFA is more sensitive than culture for VZV, and is the method of choice for all tissues except CSF, for which PCR is preferred.
CPT coding 87290
LOINC code 5882-6
Last Updated 10/24/2013 10:49:07 AM
Entry Number 977

If you have additional questions regarding this test, please call: 415-353-1667

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