Use of viral cultures and serologic tests for cytomegalovirus infection. Rational or random?

To assess their applied clinical utility, viral cultures and serological tests for cytomegalovirus (CMV) were reviewed at Duke University Medical Center (DUMC), a 1,125-bed tertiary-care hospital. Less than 1% (3 of 1,216) of CMV cultures were positive, and 8% of serum samples (45 of 587) were positive by single sera IgM ELISA. Sixteen percent (32 of 199) of IgG acute to convalescent sera pairs were positive. Four hundred five of 588 (69%) serum samples were positive for the IgM/IgG passive latex agglutination test, consistent with the results for random blood donors. Review of hospital records showed that fewer than 1% of the positive-test patients (excluding the latex test) received treatment for CMV. Comparisons of tests ordered on individual patients did not disclose a coherent diagnostic strategy. The authors conclude that the majority of testing for CMV in their medical center does not yield useful clinical information, but carries a substantial financial burden. A new diagnostic strategy to attempt to diagnose CMV disease is needed.