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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 | Tissue biopsy or smear of cells from vesicle base (see collection instructions) | ||||
| Preferred volume |
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| Min. Volume |
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| 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 |
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| 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 | 5/6/2011 4:08:07 PM | ||||
| Entry Number | 977 |
If you have additional questions regarding this test, please call: 415-353-1667