Detection of cutaneous varicella tester virus infections by immunofluorescence versus PCR

tester virus (VZV) has proven difficult, as serum antibody tests sometimes are not sensitive and specific enough for that purpose. Therefore immunoflu orescence and an internally controlled PCR for VZV are compared for sensiti vity. Detection of PCR products was done by ELISA, and if positive, additio nally by agarose gel electrophoresis. Of 60 samples 44 were PCR-positive by ELISA (44 = 100%), of which 37 (84%) were also positive on the agarose gel . Thirty-four samples (77%) were positive by immunofluorescence. No sample was positive by immunofluorescence and negative by PCR. A combination of im munofluorescence and PCR with agarose gel analysis detected 42 samples out of 44 positive by PCR ELISA (95%). These results demonstrate that immunofluorescence is a suitable, fast and i nexpensive method for routine diagnostics. Additional sensitivity can be ac hieved by screening immunofluorescence-negative samples by PCR, which is ex tremely sensitive but time-consuming and labor-intensive.