Enhancement by calcium of the detection of cytomegalovirus in cells treated with dexamethasone and dimethyl sulfoxide.

MRC-5 cultures treated with dexamethasone, dimethyl sulfoxide, and calcium were compared with untreated cultures and cultures treated with dexamethasone and dimethyl sulfoxide for the detection of human cytomegalovirus by the shell vial method. The addition of calcium resulted in significantly increased growth of human cytomegalovirus AD169. Protein studies and cell counts showed renewed cell proliferation in the treated cultures. When low-titer clinical specimens were retested, 27.5% of all positives revealed were found only on the vials treated with calcium. In a group of freshly tested specimens, the calcium-treated group accounted for 20% of the positives.