Evaluation of number of shell vial cell cultures per clinical specimen for rapid diagnosis of cytomegalovirus infection.

Specimens submitted for the diagnosis of cytomegalovirus (CMV) infection were inoculated into three (blood) or two (urine, tissue, bronchoalveolar lavage BAL]) shell vials seeded with MRC-5 cells for the diagnosis of CMV infection. We evaluated the detection of 993 specimens that were positive for CMV according to the number of shell vial cell cultures inoculated per specimen. For blood cultures, and considering one CMV-positive shell vial as 100%, inoculation of three shell vials versus one increased the detection rate of the virus by 51%. Inoculation of three shell vials compared with two yielded a 20% increase in the detection rate of CMV. For urine, tissue, and BAL specimens, inoculation of two shell vials compared with one resulted in increases of 7, 10, and 5%, respectively. For maximum detection of CMV in shell vial cell cultures, at least three vials should be inoculated with blood specimens, and two vials should be used for urine, tissue, and BAL samples.