Comparison of chemicon SimulFluor direct fluorescent antibody staining with cell culture and shell vial direct immunoperoxidase staining for detection of herpes simplex virus and with cytospin direct immunofluorescence staining for detection of varicella-zoster virus

A new rapid direct immunofluorescence assay, the SimulFluor direct fluoresc ent-antibody (DFA) assay, which can simultaneously detect herpes simplex vi rus types 1 and 2 (HSV-1 and -2) and varicella-zoster virus (VZV), was eval uated in comparison with our current standard procedures of (i) shell vial direct immunoperoxidase (shell vial IP) staining and cell culture for detec tion of HSV and (ii) cytospin DFA staining for VZV detection. A total of 51 7 vesicular, oral, genital, and skin lesion specimens were tested by all th ree procedures. For HSV detection, the SimulFluor DFA assay had an overall sensitivity, specificity, positive predictive value, and negative predictiv e value of 80.0, 98.3, 92.3, and 95.1%, respectively, when compared to cult ure. Shell vial IP staining had a sensitivity, specificity, positive predic tive value, and negative predictive value of 87.6, 100, 100, and 96.9%, res pectively, when compared with cell culture. The SimulFluor DFA assay, howev er, offers same-day, 1.5-hours results versus a 1- to 2-day wait for shell vial IP staining results and a 1- to 6-day wait for culture results for HSV . For VZV detection SimulFluor DFA staining detected 27 positive specimens as compared to 31 by our standard cytospin DFA technique-a correlation of 8 7.1%. A positive SimulFluor reaction for VZV is indicated by yellow-gold fl uorescence compared to the bright apple-green fluorescence observed by cyto spin DFA staining. There is no difference in turnaround time between the tw o assays. The SimulFluor DFA assay is a rapid immunofluorescence assay that can detect 80% of the HSV-positive specimens and 87% of the VZV-positive s pecimens with a 1.5-h turnaround time.