Comparison of methods for laboratory diagnosis of respiratory syncytial virus

Respiratory syncytial virus (RSV) still remains the main agent of lower respiratory tract infections in infants and young children, causing bronchiolitis and/or pneumonia leading to hospitalization and even to death in high-risk patients, such as premature babies. Its great impact on human health supports the need for rapid diagnostic methods in order to control and prevent the infection spread. In this study 63 samples from the respiratory tract were subjected to virological investigations usually applied in diagnostic routine: the research of RSV antigens in cells derived from the biological samples by immunofluorescence (IFD), as well as the rapid and the traditional cell culture methods (MR and MT, respectively).A third rapid test, the immunochromatographic assay TRU RSVTM (Meridian), for the research of RSV specific proteins, was applied retrospectively to the same samples stored at -80°C. Among the above considered routine methods, the most reliable for rapid diagnosis of RSV infection in our hands was IFD, which was able to reveal the greatest number of positive samples (54/63) and was therefore considered as the reference technique. The immunochromatographic assay TRU RSVTM identified 39/54 positive samples (72.2%), the bulk of which superposed with those also resulted positive with MR and/or MT (i.e. samples with high viral load). On the other hand, the immunochromatographic test was unable to detect RSV antigens in the majority of samples positive only with IFD (i.e. samples with low viral load).