Which test for cytomegalovirus has problems with false positives?

The correct choice pertains to indirect immunofluorescence as a test for cytomegalovirus (CMV). This method is known to have a higher likelihood of yielding false-positive results compared to other testing modalities. The indirect immunofluorescence assay detects antibodies bound to target antigens using fluorochrome-conjugated secondary antibodies. While this can be a sensitive approach, cross-reactivity can lead to misinterpretation of results, especially in cases with similar viral infections or when antibodies are present from previous infections.

In contrast, other tests such as the IgM antibody test are specifically designed to detect recent infections and, although they can also have issues with specificity, the indirect immunofluorescence technique is more prone to false positives in general due to the reliance on visual interpretation of stained cells, which can be affected by the presence of non-specific staining or background fluorescence.

Direct antigen detection methods, such as rapid tests for CMV antigens, tend to be more specific, while the enzyme-linked immunosorbent assay (ELISA) provides quantitative data and typically has established cut-offs that help mitigate false-positive results. Thus, the indirect immunofluorescence test is characterized by its susceptibility to false positives, making it the appropriate answer