Enhancement of varicella-zoster virus detection in A-549 shell vials by use of freeze-thawed specimens, extended incubation, and "a centrifuged, not incubated" direct detection method.
A total of 95 clinical samples were cultured for periods of 2 and 7 days in centrifuged A-549 shell vials before and after freezing and thawing of specimens. In addition, centrifuged A-549 shell vials were tested directly for varicella-zoster virus without incubation using a direct fluorescent antibody (DFA) technique. Twenty-seven specimens were positive by at least one method. The sensitivity for DFA on unincubated A-549 shell vials was 85.2%; for unfrozen 2-day cultures, 88.9%; for unfrozen 7-day cultures, 92.6%; for freeze-thaw 2-day cultures, 92.6%; and for freeze-thaw 7-day cultures, 96.3%. Freeze-thawed specimens cultured for 7 days yielded the highest number of positive results with conspicuous cell-to-cell spread as a sign of viral replication.
Division of Clinical Microbiology, University of Massachusetts Medical School, Worcester 01655, USA.
J P
JP
Brinker
G V
GV
Doern
D002460:Cell Line; D002498:Centrifugation; D019085:Fluorescent Antibody Technique, Direct; D005615:Freezing; D014645:Herpesvirus 3, Human / Q000254:growth & development / Q000302:isolation & purification*; D006801:Humans; D012680:Sensitivity and Specificity; D013048:Specimen Handling; D010948:Viral Plaque Assay; D014776:Virus Cultivation; D014779:Virus Replication